diff --git a/.circleci/config.yml b/.circleci/config.yml
index 2f2a1be81..d5cf42a8d 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -76,8 +76,9 @@ commands:
       - run:
           name: Install Clang 10
           command: |
-            echo "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" | sudo tee -a /etc/apt/sources.list
-            echo "deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" | sudo tee -a /etc/apt/sources.list
+            wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+            echo "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-10 main" | sudo tee -a /etc/apt/sources.list
+            echo "deb-src http://apt.llvm.org/focal/ llvm-toolchain-focal-10 main" | sudo tee -a /etc/apt/sources.list
             echo "APT::Acquire::Retries \"10\";" | sudo tee -a /etc/apt/apt.conf.d/80-retries # llvm.org unreliable
             sudo apt-get update -y && sudo apt-get install -y clang-10
 
@@ -86,6 +87,7 @@ commands:
       - run:
           name: Install Clang 13
           command: |
+            wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
             echo "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-13 main" | sudo tee -a /etc/apt/sources.list
             echo "deb-src http://apt.llvm.org/focal/ llvm-toolchain-focal-13 main" | sudo tee -a /etc/apt/sources.list
             echo "APT::Acquire::Retries \"10\";" | sudo tee -a /etc/apt/apt.conf.d/80-retries # llvm.org unreliable
@@ -169,7 +171,7 @@ jobs:
       - increase-max-open-files-on-macos
       - install-gflags-on-macos
       - pre-steps-macos
-      - run: ulimit -S -n 1048576 && OPT=-DCIRCLECI make V=1 J=32 -j32 check 2>&1 | .circleci/cat_ignore_eagain
+      - run: ulimit -S -n 1048576 && OPT=-DCIRCLECI make V=1 J=32 -j32 check
       - post-steps
 
   build-macos-cmake:
@@ -181,153 +183,153 @@ jobs:
       - install-cmake-on-macos
       - install-gflags-on-macos
       - pre-steps-macos
-      - run: ulimit -S -n 1048576 && (mkdir build && cd build && cmake -DWITH_GFLAGS=1 .. && make V=1 -j32 && ctest -j10) 2>&1 | .circleci/cat_ignore_eagain
+      - run: ulimit -S -n 1048576 && (mkdir build && cd build && cmake -DWITH_GFLAGS=1 .. && make V=1 -j32 && ctest -j10)
       - post-steps
 
   build-linux:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
-      - run: make V=1 J=32 -j32 check 2>&1 | .circleci/cat_ignore_eagain
+      - run: make V=1 J=32 -j32 check
       - post-steps
 
   build-linux-encrypted-env:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
-      - run: ENCRYPTED_ENV=1 make V=1 J=32 -j32 check 2>&1 | .circleci/cat_ignore_eagain
+      - run: ENCRYPTED_ENV=1 make V=1 J=32 -j32 check
       - post-steps
 
   build-linux-shared_lib-alt_namespace-status_checked:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
-      - run: ASSERT_STATUS_CHECKED=1 TEST_UINT128_COMPAT=1 ROCKSDB_MODIFY_NPHASH=1 LIB_MODE=shared OPT="-DROCKSDB_NAMESPACE=alternative_rocksdb_ns" make V=1 -j32 check 2>&1 | .circleci/cat_ignore_eagain
+      - run: ASSERT_STATUS_CHECKED=1 TEST_UINT128_COMPAT=1 ROCKSDB_MODIFY_NPHASH=1 LIB_MODE=shared OPT="-DROCKSDB_NAMESPACE=alternative_rocksdb_ns" make V=1 -j32 check
       - post-steps
 
   build-linux-release:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: large
     steps:
       - checkout # check out the code in the project directory
-      - run: make V=1 -j8 release 2>&1 | .circleci/cat_ignore_eagain
+      - run: make V=1 -j8 release
       - run: if ./db_stress --version; then false; else true; fi # ensure without gflags
       - install-gflags
-      - run: make V=1 -j8 release 2>&1 | .circleci/cat_ignore_eagain
+      - run: make V=1 -j8 release
       - run: ./db_stress --version # ensure with gflags
       - post-steps
 
   build-linux-release-rtti:
     machine:
-      image: ubuntu-1604:201903-01
+      image: ubuntu-2004:202111-02
     resource_class: large
     steps:
       - checkout # check out the code in the project directory
       - run: make clean
-      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j8 static_lib tools db_bench 2>&1 | .circleci/cat_ignore_eagain
+      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j8 static_lib tools db_bench
       - run: if ./db_stress --version; then false; else true; fi # ensure without gflags
       - run: sudo apt-get update -y && sudo apt-get install -y libgflags-dev
       - run: make clean
-      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j8 static_lib tools db_bench 2>&1 | .circleci/cat_ignore_eagain
+      - run: USE_RTTI=1 DEBUG_LEVEL=0 make V=1 -j8 static_lib tools db_bench
       - run: ./db_stress --version # ensure with gflags
 
   build-linux-lite:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
-      - run: LITE=1 make V=1 J=32 -j32 check 2>&1 | .circleci/cat_ignore_eagain
+      - run: LITE=1 make V=1 J=32 -j32 check
       - post-steps
 
   build-linux-lite-release:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: large
     steps:
       - checkout # check out the code in the project directory
-      - run: LITE=1 make V=1 -j8 release 2>&1 | .circleci/cat_ignore_eagain
+      - run: LITE=1 make V=1 -j8 release
       - run: if ./db_stress --version; then false; else true; fi # ensure without gflags
       - install-gflags
-      - run: LITE=1 make V=1 -j8 release 2>&1 | .circleci/cat_ignore_eagain
+      - run: LITE=1 make V=1 -j8 release
       - run: ./db_stress --version # ensure with gflags
       - post-steps
 
   build-linux-clang-no_test_run:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: xlarge
     steps:
       - checkout # check out the code in the project directory
       - run: sudo apt-get update -y && sudo apt-get install -y clang libgflags-dev libtbb-dev
-      - run: CC=clang CXX=clang++ USE_CLANG=1 PORTABLE=1 make V=1 -j16 all 2>&1 | .circleci/cat_ignore_eagain
+      - run: CC=clang CXX=clang++ USE_CLANG=1 PORTABLE=1 make V=1 -j16 all
       - post-steps
 
   build-linux-clang10-asan:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
       - install-clang-10
-      - run: COMPILE_WITH_ASAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 check 2>&1 | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out
+      - run: COMPILE_WITH_ASAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 check # aligned new doesn't work for reason we haven't figured out
       - post-steps
 
   build-linux-clang10-mini-tsan:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
       - install-clang-10
-      - run: COMPILE_WITH_TSAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 check 2>&1 | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out.
+      - run: COMPILE_WITH_TSAN=1 CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 check # aligned new doesn't work for reason we haven't figured out.
       - post-steps
 
   build-linux-clang10-ubsan:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
       - install-clang-10
-      - run: COMPILE_WITH_UBSAN=1 OPT="-fsanitize-blacklist=.circleci/ubsan_suppression_list.txt" CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 ubsan_check 2>&1 | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out
+      - run: COMPILE_WITH_UBSAN=1 OPT="-fsanitize-blacklist=.circleci/ubsan_suppression_list.txt" CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 ubsan_check # aligned new doesn't work for reason we haven't figured out
       - post-steps
 
   build-linux-clang10-clang-analyze:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
       - install-clang-10
       - run: sudo apt-get update -y && sudo apt-get install -y clang-tools-10
-      - run: CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 CLANG_ANALYZER="/usr/bin/clang++-10" CLANG_SCAN_BUILD=scan-build-10 USE_CLANG=1 make V=1 -j32 analyze 2>&1 | .circleci/cat_ignore_eagain # aligned new doesn't work for reason we haven't figured out. For unknown, reason passing "clang++-10" as CLANG_ANALYZER doesn't work, and we need a full path.
+      - run: CC=clang-10 CXX=clang++-10 ROCKSDB_DISABLE_ALIGNED_NEW=1 CLANG_ANALYZER="/usr/bin/clang++-10" CLANG_SCAN_BUILD=scan-build-10 USE_CLANG=1 make V=1 -j32 analyze # aligned new doesn't work for reason we haven't figured out. For unknown, reason passing "clang++-10" as CLANG_ANALYZER doesn't work, and we need a full path.
       - post-steps
 
   build-linux-cmake:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
       - install-gflags
       - upgrade-cmake
-      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 .. && make V=1 -j20 && ctest -j20) 2>&1 | .circleci/cat_ignore_eagain
+      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 .. && make V=1 -j20 && ctest -j20)
       - post-steps
 
   build-linux-cmake-ubuntu-20:
@@ -338,7 +340,7 @@ jobs:
       - pre-steps
       - install-gflags
       - install-benchmark
-      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 -DWITH_BENCHMARK=1 .. && make V=1 -j20 && ctest -j20) 2>&1 | .circleci/cat_ignore_eagain
+      - run: (mkdir build && cd build && cmake -DWITH_GFLAGS=1 -DWITH_BENCHMARK=1 .. && make V=1 -j20 && ctest -j20)
       - post-steps
 
   build-linux-unity-and-headers:
@@ -348,79 +350,69 @@ jobs:
     steps:
       - checkout # check out the code in the project directory
       - run: apt-get update -y && apt-get install -y libgflags-dev
-      - run: TEST_TMPDIR=/dev/shm && make V=1 -j8 unity_test 2>&1 | .circleci/cat_ignore_eagain
-      - run: make V=1 -j8 -k check-headers 2>&1 | .circleci/cat_ignore_eagain # could be moved to a different build
+      - run: TEST_TMPDIR=/dev/shm && make V=1 -j8 unity_test
+      - run: make V=1 -j8 -k check-headers # could be moved to a different build
       - post-steps
 
-  build-linux-gcc-4_8-no_test_run:
+  build-linux-gcc-7:
     machine:
       image: ubuntu-1604:202104-01
-    resource_class: large
+    resource_class: 2xlarge
     steps:
       - pre-steps
-      - run: sudo apt-get update -y && sudo apt-get install gcc-4.8 g++-4.8 libgflags-dev
-      - run: CC=gcc-4.8 CXX=g++-4.8 V=1 SKIP_LINK=1 make -j8 all 2>&1 | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
+      - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-7 g++-7 libgflags-dev
+      - run: CC=gcc-7 CXX=g++-7 V=1 make -j32 check 2>&1 | .circleci/cat_ignore_eagain
       - post-steps
 
   build-linux-gcc-8-no_test_run:
     machine:
-      image: ubuntu-2004:202010-01
-    resource_class: large
-    steps:
-      - pre-steps
-      - run: sudo apt-get update -y && sudo apt-get install gcc-8 g++-8 libgflags-dev
-      - run: CC=gcc-8 CXX=g++-8 V=1 SKIP_LINK=1 make -j8 all 2>&1 | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
-      - post-steps
-
-  build-linux-gcc-9-no_test_run:
-    machine:
-      image: ubuntu-2004:202010-01
+      image: ubuntu-1604:202104-01
     resource_class: large
     steps:
       - pre-steps
-      - run: sudo apt-get update -y && sudo apt-get install gcc-9 g++-9 libgflags-dev
-      - run: CC=gcc-9 CXX=g++-9 V=1 SKIP_LINK=1 make -j8 all 2>&1 | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
+      - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-8 g++-8 libgflags-dev
+      - run: CC=gcc-8 CXX=g++-8 V=1 make -j8 all 2>&1 | .circleci/cat_ignore_eagain
       - post-steps
 
   build-linux-gcc-10-cxx20-no_test_run:
     machine:
-      image: ubuntu-2004:202010-01
+      image: ubuntu-2004:202111-02
     resource_class: xlarge
     steps:
       - pre-steps
       - run: sudo apt-get update -y && sudo apt-get install gcc-10 g++-10 libgflags-dev
-      - run: CC=gcc-10 CXX=g++-10 V=1 SKIP_LINK=1 ROCKSDB_CXX_STANDARD=c++20 make -j16 all 2>&1 | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
+      - run: CC=gcc-10 CXX=g++-10 V=1 SKIP_LINK=1 ROCKSDB_CXX_STANDARD=c++20 make -j16 all # Linking broken because libgflags compiled with newer ABI
       - post-steps
 
   build-linux-gcc-11-no_test_run:
     machine:
-      image: ubuntu-2004:202010-01
+      image: ubuntu-2004:202111-02
     resource_class: xlarge
     steps:
       - pre-steps
-      - run: sudo apt-get update -y && sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get install gcc-11 g++-11 libgflags-dev
-      - run: CC=gcc-11 CXX=g++-11 V=1 SKIP_LINK=1 make -j16 all 2>&1 | .circleci/cat_ignore_eagain # Linking broken because libgflags compiled with newer ABI
+      - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-11 g++-11 libgflags-dev
+      - run: CC=gcc-11 CXX=g++-11 V=1 SKIP_LINK=1 make -j16 all # Linking broken because libgflags compiled with newer ABI
       - post-steps
 
   build-linux-clang-13-no_test_run:
     machine:
-      image: ubuntu-2004:202010-01
+      image: ubuntu-2004:202111-02
     resource_class: xlarge
     steps:
       - pre-steps
       - install-clang-13
-      - run: CC=clang-13 CXX=clang++-13 USE_CLANG=1 make -j16 all 2>&1 | .circleci/cat_ignore_eagain
+      - run: CC=clang-13 CXX=clang++-13 USE_CLANG=1 make -j16 all
       - post-steps
 
   # This job is only to make sure the microbench tests are able to run, the benchmark result is not meaningful as the CI host is changing.
   build-linux-microbench:
     machine:
-      image: ubuntu-2004:202010-01
+      image: ubuntu-2004:202111-02
     resource_class: xlarge
     steps:
       - pre-steps
       - install-benchmark
-      - run: DEBUG_LEVEL=0 make microbench 2>&1 | .circleci/cat_ignore_eagain
+      - run: DEBUG_LEVEL=0 make microbench
       - post-steps
 
   build-windows:
@@ -493,7 +485,7 @@ jobs:
 
   build-linux-java:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: large
     environment:
       JAVA_HOME: /usr/lib/jvm/java-1.8.0-openjdk-amd64
@@ -509,15 +501,15 @@ jobs:
             which javac && javac -version
       - run:
           name: "Build RocksDBJava Shared Library"
-          command: make V=1 J=8 -j8 rocksdbjava 2>&1 | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 rocksdbjava
       - run:
           name: "Test RocksDBJava"
-          command: make V=1 J=8 -j8 jtest 2>&1 | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 jtest
       - post-steps
 
   build-linux-java-static:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: large
     environment:
       JAVA_HOME: /usr/lib/jvm/java-1.8.0-openjdk-amd64
@@ -533,7 +525,7 @@ jobs:
             which javac && javac -version
       - run:
           name: "Build RocksDBJava Static Library"
-          command: make V=1 J=8 -j8 rocksdbjavastatic 2>&1 | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 rocksdbjavastatic
       - post-steps
 
   build-macos-java:
@@ -557,10 +549,10 @@ jobs:
             which javac && javac -version
       - run:
           name: "Build RocksDBJava Shared Library"
-          command: make V=1 J=8 -j8 rocksdbjava 2>&1 | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 rocksdbjava
       - run:
           name: "Test RocksDBJava"
-          command: make V=1 J=8 -j8 jtest 2>&1 | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 jtest
       - post-steps
 
   build-macos-java-static:
@@ -584,7 +576,7 @@ jobs:
             which javac && javac -version
       - run:
           name: "Build RocksDBJava x86 and ARM Static Libraries"
-          command: make V=1 J=8 -j8 rocksdbjavastaticosx 2>&1 | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 rocksdbjavastaticosx
       - post-steps
 
   build-macos-java-static-universal:
@@ -608,12 +600,12 @@ jobs:
             which javac && javac -version
       - run:
           name: "Build RocksDBJava Universal Binary Static Library"
-          command: make V=1 J=8 -j8 rocksdbjavastaticosx_ub 2>&1 | .circleci/cat_ignore_eagain
+          command: make V=1 J=8 -j8 rocksdbjavastaticosx_ub
       - post-steps
 
   build-examples:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: large
     steps:
       - pre-steps
@@ -621,12 +613,12 @@ jobs:
       - run:
           name: "Build examples"
           command: |
-            OPT=-DTRAVIS V=1 make -j4 static_lib && cd examples && make -j4 | ../.circleci/cat_ignore_eagain
+            OPT=-DTRAVIS V=1 make -j4 static_lib && cd examples && make -j4
       - post-steps
 
   build-cmake-mingw:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
@@ -649,7 +641,7 @@ jobs:
 
   build-linux-non-shm:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     parameters:
       start_test:
@@ -679,27 +671,27 @@ jobs:
 
   build-linux-arm-test-full:
     machine:
-      image: ubuntu-2004:202101-01
+      image: ubuntu-2004:202111-02
     resource_class: arm.large
     steps:
       - pre-steps
       - install-gflags
-      - run: make V=1 J=4 -j4 check 2>&1 | .circleci/cat_ignore_eagain
+      - run: make V=1 J=4 -j4 check
       - post-steps
 
   build-linux-arm:
     machine:
-      image: ubuntu-2004:202101-01
+      image: ubuntu-2004:202111-02
     resource_class: arm.large
     steps:
       - pre-steps
       - install-gflags
-      - run: ROCKSDBTESTS_PLATFORM_DEPENDENT=only make V=1 J=4 -j4 all_but_some_tests check_some 2>&1 | .circleci/cat_ignore_eagain
+      - run: ROCKSDBTESTS_PLATFORM_DEPENDENT=only make V=1 J=4 -j4 all_but_some_tests check_some
       - post-steps
 
   build-linux-arm-cmake-no_test_run:
     machine:
-      image: ubuntu-2004:202101-01
+      image: ubuntu-2004:202111-02
     resource_class: arm.large
     environment:
       JAVA_HOME: /usr/lib/jvm/java-8-openjdk-arm64
@@ -732,7 +724,7 @@ jobs:
 
   build-format-compatible:
     machine:
-      image: ubuntu-1604:202104-01
+      image: ubuntu-2004:202111-02
     resource_class: 2xlarge
     steps:
       - pre-steps
@@ -849,9 +841,8 @@ workflows:
     jobs:
       - build-linux-clang-no_test_run
       - build-linux-clang-13-no_test_run
-      - build-linux-gcc-4_8-no_test_run
+      - build-linux-gcc-7
       - build-linux-gcc-8-no_test_run
-      - build-linux-gcc-9-no_test_run
       - build-linux-gcc-10-cxx20-no_test_run
       - build-linux-gcc-11-no_test_run
       - build-linux-arm-cmake-no_test_run
diff --git a/.travis.yml b/.travis.yml
index 3a71b264b..8c2d23719 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -43,7 +43,6 @@ env:
   - JOB_NAME=cmake-gcc9 # 3-5 minutes
   - JOB_NAME=cmake-gcc9-c++20 # 3-5 minutes
   - JOB_NAME=cmake-mingw # 3 minutes
-  - JOB_NAME=make-gcc4.8
   - JOB_NAME=status_checked
 
 matrix:
@@ -51,21 +50,12 @@ matrix:
   - os : linux
     arch: arm64
     env: JOB_NAME=cmake-mingw
-  - os : linux
-    arch: arm64
-    env: JOB_NAME=make-gcc4.8
   - os: linux
     arch: ppc64le
     env: JOB_NAME=cmake-mingw
-  - os: linux
-    arch: ppc64le
-    env: JOB_NAME=make-gcc4.8
   - os: linux
     arch: s390x
     env: JOB_NAME=cmake-mingw
-  - os: linux
-    arch: s390x
-    env: JOB_NAME=make-gcc4.8
   - os: linux
     compiler: clang
   - if: type = pull_request AND commit_message !~ /FULL_CI/
@@ -210,6 +200,7 @@ matrix:
     env: JOB_NAME=status_checked
 
 install:
+  -  CC=gcc-7 && CXX=g++-7
   - if [ "${JOB_NAME}" == cmake-gcc8 ]; then
       sudo apt-get install -y g++-8 || exit $?;
       CC=gcc-8 && CXX=g++-8;
@@ -221,9 +212,8 @@ install:
   - if [ "${JOB_NAME}" == cmake-mingw ]; then
       sudo apt-get install -y mingw-w64 || exit $?;
     fi
-  - if [ "${JOB_NAME}" == make-gcc4.8 ]; then
-      sudo apt-get install -y g++-4.8 || exit $?;
-      CC=gcc-4.8 && CXX=g++-4.8;
+  - if [ "${CXX}" == "g++-7" ]; then
+      sudo apt-get install -y g++-7 || exit $?;
     fi
   - |
     if [[ "${JOB_NAME}" == cmake* ]]; then
@@ -293,9 +283,6 @@ script:
 
       mkdir build && cd build && cmake -DCMAKE_BUILD_TYPE=Release -DWITH_TESTS=0 -DWITH_GFLAGS=0 -DWITH_BENCHMARK_TOOLS=0 -DWITH_TOOLS=0 -DWITH_CORE_TOOLS=1 .. && make -j4 && cd  .. && rm -rf build && mkdir build && cd build && cmake -DJNI=1 .. -DCMAKE_BUILD_TYPE=Release $OPT && make -j4 rocksdb rocksdbjni
       ;;
-    make-gcc4.8)
-      OPT=-DTRAVIS LIB_MODE=shared V=1 SKIP_LINK=1 make -j4 all && [ "Linking broken because libgflags compiled with newer ABI" ]
-      ;;
     status_checked)
       OPT=-DTRAVIS LIB_MODE=shared V=1 ASSERT_STATUS_CHECKED=1 make -j4 check_some
       ;;
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b1f4a3cc7..c9032ba92 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,7 @@
 #        cd build
 # 3. Run cmake to generate project files for Windows, add more options to enable required third-party libraries.
 #    See thirdparty.inc for more information.
-#        sample command: cmake -G "Visual Studio 15 Win64" -DCMAKE_BUILD_TYPE=Release -DWITH_GFLAGS=1 -DWITH_SNAPPY=1 -DWITH_JEMALLOC=1 -DWITH_JNI=1 ..
+#        sample command: cmake -G "Visual Studio 16 2019" -DCMAKE_BUILD_TYPE=Release -DWITH_GFLAGS=1 -DWITH_SNAPPY=1 -DWITH_JEMALLOC=1 -DWITH_JNI=1 ..
 # 4. Then build the project in debug mode (you may want to add /m[:<N>] flag to run msbuild in <N> parallel threads
 #                                          or simply /m to use all avail cores)
 #        msbuild rocksdb.sln
@@ -27,7 +27,7 @@
 #
 # Linux:
 #
-# 1. Install a recent toolchain such as devtoolset-3 if you're on a older distro. C++11 required.
+# 1. Install a recent toolchain if you're on a older distro. C++17 required (GCC >= 7, Clang >= 5)
 # 2. mkdir build; cd build
 # 3. cmake ..
 # 4. make -j
@@ -92,7 +92,7 @@ else()
 endif()
 
 if( NOT DEFINED CMAKE_CXX_STANDARD )
-  set(CMAKE_CXX_STANDARD 11)
+  set(CMAKE_CXX_STANDARD 17)
 endif()
 
 include(CMakeDependentOption)
@@ -342,7 +342,7 @@ endif()
 
 # Check if -latomic is required or not
 if (NOT MSVC)
-  set(CMAKE_REQUIRED_FLAGS "--std=c++11")
+  set(CMAKE_REQUIRED_FLAGS "--std=c++17")
   CHECK_CXX_SOURCE_COMPILES("
 #include <atomic>
 std::atomic<uint64_t> x(0);
@@ -369,18 +369,8 @@ endif()
 # Reset the required flags
 set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
 
-CHECK_CXX_SOURCE_COMPILES("
-#if defined(_MSC_VER) && !defined(__thread)
-#define __thread __declspec(thread)
-#endif
-int main() {
-  static __thread int tls;
-  (void)tls;
-}
-" HAVE_THREAD_LOCAL)
-if(HAVE_THREAD_LOCAL)
-  add_definitions(-DROCKSDB_SUPPORT_THREAD_LOCAL)
-endif()
+# thread_local is part of C++11 and later (TODO: clean up this define)
+add_definitions(-DROCKSDB_SUPPORT_THREAD_LOCAL)
 
 option(WITH_IOSTATS_CONTEXT "Enable IO stats context" ON)
 if (NOT WITH_IOSTATS_CONTEXT)
diff --git a/HISTORY.md b/HISTORY.md
index 708d7cbf2..226956e08 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -5,6 +5,7 @@
 * Fixed more cases of EventListener::OnTableFileCreated called with OK status, file_size==0, and no SST file kept. Now the status is Aborted.
 
 ### Public API changes
+* Require C++17 compatible compiler (GCC >= 7, Clang >= 5, Visual Studio >= 2017). See #9388.
 * Remove HDFS support from main repo.
 * Remove librados support from main repo.
 * Remove obsolete backupable_db.h and type alias `BackupableDBOptions`. Use backup_engine.h and `BackupEngineOptions`. Similar renamings are in the C and Java APIs.
diff --git a/INSTALL.md b/INSTALL.md
index a1521fb51..96ece3d2d 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -6,7 +6,7 @@ than release mode.
 
 RocksDB's library should be able to compile without any dependency installed,
 although we recommend installing some compression libraries (see below).
-We do depend on newer gcc/clang with C++11 support.
+We do depend on newer gcc/clang with C++17 support (GCC >= 7, Clang >= 5).
 
 There are few options when compiling RocksDB:
 
@@ -50,7 +50,7 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
 ## Supported platforms
 
 * **Linux - Ubuntu**
-    * Upgrade your gcc to version at least 4.8 to get C++11 support.
+    * Upgrade your gcc to version at least 7 to get C++17 support.
     * Install gflags. First, try: `sudo apt-get install libgflags-dev`
       If this doesn't work and you're using Ubuntu, here's a nice tutorial:
       (http://askubuntu.com/questions/312173/installing-gflags-12-04)
@@ -62,8 +62,7 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
     * Install zstandard: `sudo apt-get install libzstd-dev`.
 
 * **Linux - CentOS / RHEL**
-    * Upgrade your gcc to version at least 4.8 to get C++11 support:
-      `yum install gcc48-c++`
+    * Upgrade your gcc to version at least 7 to get C++17 support
     * Install gflags:
 
               git clone https://github.com/gflags/gflags.git
@@ -113,11 +112,11 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
               make && sudo make install
 
 * **OS X**:
-    * Install latest C++ compiler that supports C++ 11:
+    * Install latest C++ compiler that supports C++ 17:
         * Update XCode:  run `xcode-select --install` (or install it from XCode App's settting).
         * Install via [homebrew](http://brew.sh/).
             * If you're first time developer in MacOS, you still need to run: `xcode-select --install` in your command line.
-            * run `brew tap homebrew/versions; brew install gcc48 --use-llvm` to install gcc 4.8 (or higher).
+            * run `brew tap homebrew/versions; brew install gcc7 --use-llvm` to install gcc 7 (or higher).
     * run `brew install rocksdb`
 
 * **FreeBSD** (11.01):
@@ -160,7 +159,7 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
 
     * Install the dependencies for RocksDB:
 
-        pkg_add gmake gflags snappy bzip2 lz4 zstd git jdk bash findutils gnuwatch 
+        pkg_add gmake gflags snappy bzip2 lz4 zstd git jdk bash findutils gnuwatch
 
     * Build RocksDB from source:
 
@@ -182,13 +181,13 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
 * **Windows**:
   * For building with MS Visual Studio 13 you will need Update 4 installed.
   * Read and follow the instructions at CMakeLists.txt
-  * Or install via [vcpkg](https://github.com/microsoft/vcpkg) 
+  * Or install via [vcpkg](https://github.com/microsoft/vcpkg)
        * run `vcpkg install rocksdb:x64-windows`
 
 * **AIX 6.1**
     * Install AIX Toolbox rpms with gcc
     * Use these environment variables:
-  
+
              export PORTABLE=1
              export CC=gcc
              export AR="ar -X64"
@@ -199,9 +198,9 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
              export LIBPATH=/opt/freeware/lib
              export JAVA_HOME=/usr/java8_64
              export PATH=/opt/freeware/bin:$PATH
-  
+
 * **Solaris Sparc**
-    * Install GCC 4.8.2 and higher.
+    * Install GCC 7 and higher.
     * Use these environment variables:
 
              export CC=gcc
@@ -210,4 +209,3 @@ to build a portable binary, add `PORTABLE=1` before your make commands, like thi
              export EXTRA_LDFLAGS=-m64
              export PORTABLE=1
              export PLATFORM_LDFLAGS="-static-libstdc++ -static-libgcc"
-
diff --git a/Makefile b/Makefile
index 0ec9ceaa0..c4b8dc57f 100644
--- a/Makefile
+++ b/Makefile
@@ -215,7 +215,7 @@ am__v_AR_0 = @echo "  AR      " $@;
 am__v_AR_1 =
 
 AM_LINK = $(AM_V_CCLD)$(CXX) -L. $(patsubst lib%.a, -l%, $(patsubst lib%.$(PLATFORM_SHARED_EXT), -l%, $^)) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
-AM_SHARE = $(AM_V_CCLD) $(CXX) $(PLATFORM_SHARED_LDFLAGS)$@ -L. $(patsubst lib%.$(PLATFORM_SHARED_EXT), -l%, $^) $(LDFLAGS) -o $@
+AM_SHARE = $(AM_V_CCLD) $(CXX) $(PLATFORM_SHARED_LDFLAGS)$@ -L. $(patsubst lib%.$(PLATFORM_SHARED_EXT), -l%, $^) $(EXEC_LDFLAGS) $(LDFLAGS) -o $@
 
 # Detect what platform we're building on.
 # Export some common variables that might have been passed as Make variables
@@ -574,27 +574,29 @@ check-headers: $(HEADER_OK_FILES)
 
 # options_settable_test doesn't pass with UBSAN as we use hack in the test
 ifdef COMPILE_WITH_UBSAN
-        TESTS := $(shell echo $(TESTS) | sed 's/\boptions_settable_test\b//g')
+TESTS := $(shell echo $(TESTS) | sed 's/\boptions_settable_test\b//g')
 endif
 ifdef ASSERT_STATUS_CHECKED
-	# TODO: finish fixing all tests to pass this check
-	TESTS_FAILING_ASC = \
-		c_test \
-		env_test \
-		range_locking_test \
-		testutil_test \
+# TODO: finish fixing all tests to pass this check
+TESTS_FAILING_ASC = \
+	c_test \
+	env_test \
+	range_locking_test \
+	testutil_test \
 
-	# Since we have very few ASC exclusions left, excluding them from
-	# the build is the most convenient way to exclude them from testing
-	TESTS := $(filter-out $(TESTS_FAILING_ASC),$(TESTS))
+# Since we have very few ASC exclusions left, excluding them from
+# the build is the most convenient way to exclude them from testing
+TESTS := $(filter-out $(TESTS_FAILING_ASC),$(TESTS))
 endif
 
 ROCKSDBTESTS_SUBSET ?= $(TESTS)
 
+# c_test - doesn't use gtest
 # env_test - suspicious use of test::TmpDir
 # deletefile_test - serial because it generates giant temporary files in
 #   its various tests. Parallel can fill up your /dev/shm
 NON_PARALLEL_TEST = \
+	c_test \
 	env_test \
 	deletefile_test \
 
@@ -852,7 +854,7 @@ endif
 
 parallel_tests = $(patsubst %,parallel_%,$(PARALLEL_TEST))
 .PHONY: gen_parallel_tests $(parallel_tests)
-$(parallel_tests): $(PARALLEL_TEST)
+$(parallel_tests):
 	$(AM_V_at)TEST_BINARY=$(patsubst parallel_%,%,$@); \
   TEST_NAMES=` \
     (./$$TEST_BINARY --gtest_list_tests || echo "  $${TEST_BINARY}__list_tests_failure") \
@@ -2236,7 +2238,7 @@ rocksdbjavastaticosx_ub: rocksdbjavastaticosx_archs
 	lipo -create -output ./java/target/$(ROCKSDBJNILIB) java/target/librocksdbjni-osx-x86_64.jnilib java/target/librocksdbjni-osx-arm64.jnilib
 	$(MAKE) rocksdbjavastatic_jar
 
-rocksdbjavastaticosx_archs: 
+rocksdbjavastaticosx_archs:
 	$(MAKE) rocksdbjavastaticosx_arch_x86_64
 	$(MAKE) rocksdbjavastaticosx_arch_arm64
 
diff --git a/appveyor.yml b/appveyor.yml
deleted file mode 100644
index 1cb23aa2c..000000000
--- a/appveyor.yml
+++ /dev/null
@@ -1,74 +0,0 @@
-version: 1.0.{build}
-
-image: Visual Studio 2019
-
-environment:
-  JAVA_HOME: C:\Program Files\Java\jdk1.8.0
-  THIRDPARTY_HOME: $(APPVEYOR_BUILD_FOLDER)\thirdparty
-  SNAPPY_HOME: $(THIRDPARTY_HOME)\snappy-1.1.7
-  SNAPPY_INCLUDE: $(SNAPPY_HOME);$(SNAPPY_HOME)\build
-  SNAPPY_LIB_DEBUG: $(SNAPPY_HOME)\build\Debug\snappy.lib
-  SNAPPY_LIB_RELEASE: $(SNAPPY_HOME)\build\Release\snappy.lib
-  LZ4_HOME: $(THIRDPARTY_HOME)\lz4-1.8.3
-  LZ4_INCLUDE: $(LZ4_HOME)\lib
-  LZ4_LIB_DEBUG: $(LZ4_HOME)\visual\VS2010\bin\x64_Debug\liblz4_static.lib
-  LZ4_LIB_RELEASE: $(LZ4_HOME)\visual\VS2010\bin\x64_Release\liblz4_static.lib
-  ZSTD_HOME: $(THIRDPARTY_HOME)\zstd-1.4.0
-  ZSTD_INCLUDE: $(ZSTD_HOME)\lib;$(ZSTD_HOME)\lib\dictBuilder
-  ZSTD_LIB_DEBUG: $(ZSTD_HOME)\build\VS2010\bin\x64_Debug\libzstd_static.lib
-  ZSTD_LIB_RELEASE: $(ZSTD_HOME)\build\VS2010\bin\x64_Release\libzstd_static.lib
-  matrix:
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      CMAKE_GENERATOR: Visual Studio 14 Win64
-      DEV_ENV: C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\devenv.com
-
-install:
-  - md %THIRDPARTY_HOME%
-  - echo "Building Snappy dependency..."
-  - cd %THIRDPARTY_HOME%
-  - curl --fail --silent --show-error --output snappy-1.1.7.zip --location https://github.com/google/snappy/archive/1.1.7.zip
-  - unzip snappy-1.1.7.zip
-  - cd snappy-1.1.7
-  - mkdir build
-  - cd build
-  - if DEFINED CMAKE_PLATEFORM_NAME (set "PLATEFORM_OPT=-A %CMAKE_PLATEFORM_NAME%")
-  - cmake .. -G "%CMAKE_GENERATOR%" %PLATEFORM_OPT%
-  - msbuild Snappy.sln /p:Configuration=Debug /p:Platform=x64
-  - msbuild Snappy.sln /p:Configuration=Release /p:Platform=x64
-  - echo "Building LZ4 dependency..."
-  - cd %THIRDPARTY_HOME%
-  - curl --fail --silent --show-error --output lz4-1.8.3.zip --location https://github.com/lz4/lz4/archive/v1.8.3.zip
-  - unzip lz4-1.8.3.zip
-  - cd lz4-1.8.3\visual\VS2010
-  - ps: $CMD="$Env:DEV_ENV"; & $CMD lz4.sln /upgrade
-  - msbuild lz4.sln /p:Configuration=Debug /p:Platform=x64
-  - msbuild lz4.sln /p:Configuration=Release /p:Platform=x64
-  - echo "Building ZStd dependency..."
-  - cd %THIRDPARTY_HOME%
-  - curl --fail --silent --show-error --output zstd-1.4.0.zip --location https://github.com/facebook/zstd/archive/v1.4.0.zip
-  - unzip zstd-1.4.0.zip
-  - cd zstd-1.4.0\build\VS2010
-  - ps: $CMD="$Env:DEV_ENV"; & $CMD zstd.sln /upgrade
-  - msbuild zstd.sln /p:Configuration=Debug /p:Platform=x64
-  - msbuild zstd.sln /p:Configuration=Release /p:Platform=x64
-
-before_build:
-  - md %APPVEYOR_BUILD_FOLDER%\build
-  - cd %APPVEYOR_BUILD_FOLDER%\build
-  - if DEFINED CMAKE_PLATEFORM_NAME (set "PLATEFORM_OPT=-A %CMAKE_PLATEFORM_NAME%")
-  - cmake .. -G "%CMAKE_GENERATOR%" %PLATEFORM_OPT% %CMAKE_OPT% -DCMAKE_BUILD_TYPE=Debug -DOPTDBG=1 -DPORTABLE=1 -DSNAPPY=1 -DLZ4=1 -DZSTD=1 -DXPRESS=1 -DJNI=1 -DWITH_ALL_TESTS=0
-  - cd ..
-
-build:
-  project: build\rocksdb.sln
-  parallel: true
-  verbosity: normal
-
-test:
-
-test_script:
-  - ps: build_tools\run_ci_db_test.ps1 -SuiteRun db_basic_test,env_basic_test -Concurrency 8
-
-on_failure:
-  - cmd: 7z a build-failed.zip %APPVEYOR_BUILD_FOLDER%\build\ && appveyor PushArtifact build-failed.zip
-
diff --git a/build_tools/build_detect_platform b/build_tools/build_detect_platform
index 8b3470c94..b1f8f1aed 100755
--- a/build_tools/build_detect_platform
+++ b/build_tools/build_detect_platform
@@ -45,11 +45,11 @@ if test -z "$OUTPUT"; then
   exit 1
 fi
 
-# we depend on C++11, but should be compatible with newer standards
+# we depend on C++17, but should be compatible with newer standards
 if [ "$ROCKSDB_CXX_STANDARD" ]; then
   PLATFORM_CXXFLAGS="-std=$ROCKSDB_CXX_STANDARD"
 else
-  PLATFORM_CXXFLAGS="-std=c++11"
+  PLATFORM_CXXFLAGS="-std=c++17"
 fi
 
 # we currently depend on POSIX platform
@@ -794,24 +794,8 @@ if [ "$?" = 0 ]; then
   COMMON_FLAGS="$COMMON_FLAGS -DHAVE_UINT128_EXTENSION"
 fi
 
-# iOS doesn't support thread-local storage, but this check would erroneously
-# succeed because the cross-compiler flags are added by the Makefile, not this
-# script.
-if [ "$PLATFORM" != IOS ]; then
-  $CXX $COMMON_FLAGS -x c++ - -o test.o 2>/dev/null <<EOF
-  #if defined(_MSC_VER) && !defined(__thread)
-  #define __thread __declspec(thread)
-  #endif
-  int main() {
-    static __thread int tls;
-    (void)tls;
-  }
-EOF
-  if [ "$?" = 0 ]; then
-    COMMON_FLAGS="$COMMON_FLAGS -DROCKSDB_SUPPORT_THREAD_LOCAL"
-  fi
-fi
-
+# thread_local is part of C++11 and later (TODO: clean up this define)
+COMMON_FLAGS="$COMMON_FLAGS -DROCKSDB_SUPPORT_THREAD_LOCAL"
 
 if [ "$FBCODE_BUILD" != "true" -a "$PLATFORM" = OS_LINUX ]; then
   $CXX $COMMON_FLAGS $PLATFORM_SHARED_CFLAGS -x c++ -c - -o test_dl.o 2>/dev/null <<EOF
diff --git a/cache/lru_cache_test.cc b/cache/lru_cache_test.cc
index 67552dc4d..e8eb63826 100644
--- a/cache/lru_cache_test.cc
+++ b/cache/lru_cache_test.cc
@@ -511,10 +511,12 @@ TEST_F(LRUSecondaryCacheTest, BasicFailTest) {
 
   Random rnd(301);
   std::string str1 = rnd.RandomString(1020);
-  TestItem* item1 = new TestItem(str1.data(), str1.length());
-  ASSERT_NOK(cache->Insert("k1", item1, nullptr, str1.length()));
-  ASSERT_OK(cache->Insert("k1", item1, &LRUSecondaryCacheTest::helper_,
+  auto item1 = std::make_unique<TestItem>(str1.data(), str1.length());
+  ASSERT_TRUE(cache->Insert("k1", item1.get(), nullptr, str1.length())
+                  .IsInvalidArgument());
+  ASSERT_OK(cache->Insert("k1", item1.get(), &LRUSecondaryCacheTest::helper_,
                           str1.length()));
+  item1.release();  // Appease clang-analyze "potential memory leak"
 
   Cache::Handle* handle;
   handle = cache->Lookup("k2", nullptr, test_item_creator, Cache::Priority::LOW,
diff --git a/env/mock_env.cc b/env/mock_env.cc
index a85339ea2..0ab0f981f 100644
--- a/env/mock_env.cc
+++ b/env/mock_env.cc
@@ -790,7 +790,11 @@ IOStatus MockFileSystem::GetChildren(const std::string& dir,
                                      IODebugContext* /*dbg*/) {
   MutexLock lock(&mutex_);
   bool found_dir = GetChildrenInternal(dir, result);
+#ifndef __clang_analyzer__
   return found_dir ? IOStatus::OK() : IOStatus::NotFound(dir);
+#else
+  return found_dir ? IOStatus::OK() : IOStatus::NotFound();
+#endif
 }
 
 void MockFileSystem::DeleteFileInternal(const std::string& fname) {
diff --git a/examples/Makefile b/examples/Makefile
index faee6f06b..2fd162136 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -19,16 +19,16 @@ CFLAGS += -Wstrict-prototypes
 all: simple_example column_families_example compact_files_example c_simple_example optimistic_transaction_example transaction_example compaction_filter_example options_file_example
 
 simple_example: librocksdb simple_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 column_families_example: librocksdb column_families_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 compaction_filter_example: librocksdb compaction_filter_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 compact_files_example: librocksdb compact_files_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 .c.o:
 	$(CC) $(CFLAGS) -c $< -o $@ -I../include
@@ -37,16 +37,16 @@ c_simple_example: librocksdb c_simple_example.o
 	$(CXX) $@.o -o$@ ../librocksdb.a $(PLATFORM_LDFLAGS) $(EXEC_LDFLAGS)
 
 optimistic_transaction_example: librocksdb optimistic_transaction_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 transaction_example: librocksdb transaction_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 options_file_example: librocksdb options_file_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 multi_processes_example: librocksdb multi_processes_example.cc
-	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++11 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
+	$(CXX) $(CXXFLAGS) $@.cc -o$@ ../librocksdb.a -I../include -O2 -std=c++17 $(PLATFORM_LDFLAGS) $(PLATFORM_CXXFLAGS) $(EXEC_LDFLAGS)
 
 clean:
 	rm -rf ./simple_example ./column_families_example ./compact_files_example ./compaction_filter_example ./c_simple_example c_simple_example.o ./optimistic_transaction_example ./transaction_example ./options_file_example ./multi_processes_example
diff --git a/include/rocksdb/c.h b/include/rocksdb/c.h
index e26de3a50..4b162ff39 100644
--- a/include/rocksdb/c.h
+++ b/include/rocksdb/c.h
@@ -340,7 +340,7 @@ extern ROCKSDB_LIBRARY_API rocksdb_t* rocksdb_open_as_secondary_column_families(
     const char* secondary_path, int num_column_families,
     const char* const* column_family_names,
     const rocksdb_options_t* const* column_family_options,
-    rocksdb_column_family_handle_t** colummn_family_handles, char** errptr);
+    rocksdb_column_family_handle_t** column_family_handles, char** errptr);
 
 extern ROCKSDB_LIBRARY_API char** rocksdb_list_column_families(
     const rocksdb_options_t* options, const char* name, size_t* lencf,
diff --git a/include/rocksdb/slice.h b/include/rocksdb/slice.h
index c17b32c5c..3722fc4e6 100644
--- a/include/rocksdb/slice.h
+++ b/include/rocksdb/slice.h
@@ -18,15 +18,12 @@
 
 #pragma once
 
-#include <assert.h>
-#include <stddef.h>
-#include <string.h>
+#include <cassert>
+#include <cstddef>
 #include <cstdio>
+#include <cstring>
 #include <string>
-
-#ifdef __cpp_lib_string_view
-#include <string_view>
-#endif
+#include <string_view>  // RocksDB now requires C++17 support
 
 #include "rocksdb/cleanable.h"
 
@@ -44,11 +41,9 @@ class Slice {
   /* implicit */
   Slice(const std::string& s) : data_(s.data()), size_(s.size()) {}
 
-#ifdef __cpp_lib_string_view
   // Create a slice that refers to the same contents as "sv"
   /* implicit */
-  Slice(std::string_view sv) : data_(sv.data()), size_(sv.size()) {}
-#endif
+  Slice(const std::string_view& sv) : data_(sv.data()), size_(sv.size()) {}
 
   // Create a slice that refers to s[0,strlen(s)-1]
   /* implicit */
@@ -96,12 +91,10 @@ class Slice {
   // when hex is true, returns a string of twice the length hex encoded (0-9A-F)
   std::string ToString(bool hex = false) const;
 
-#ifdef __cpp_lib_string_view
   // Return a string_view that references the same data as this slice.
   std::string_view ToStringView() const {
     return std::string_view(data_, size_);
   }
-#endif
 
   // Decodes the current slice interpreted as an hexadecimal string into result,
   // if successful returns true, if this isn't a valid hex string
diff --git a/port/port_posix.h b/port/port_posix.h
index fdf90c236..1bb0841fd 100644
--- a/port/port_posix.h
+++ b/port/port_posix.h
@@ -25,6 +25,11 @@
 
 #define ROCKSDB_NOEXCEPT noexcept
 
+// thread_local is part of C++11 and later (TODO: clean up this define)
+#ifndef __thread
+#define __thread thread_local
+#endif
+
 #undef PLATFORM_IS_LITTLE_ENDIAN
 #if defined(OS_MACOSX)
   #include <machine/endian.h>
diff --git a/port/win/port_win.h b/port/win/port_win.h
index 98c53cf17..a1d8e02bf 100644
--- a/port/win/port_win.h
+++ b/port/win/port_win.h
@@ -60,10 +60,9 @@ using ssize_t = SSIZE_T;
 #ifdef _MSC_VER
 #define __attribute__(A)
 
-// Thread local storage on Linux
-// There is thread_local in C++11
+// thread_local is part of C++11 and later (TODO: clean up this define)
 #ifndef __thread
-#define __thread __declspec(thread)
+#define __thread thread_local
 #endif
 
 #endif
diff --git a/util/gflags_compat.h b/util/gflags_compat.h
index ddd3747fa..c12c7e2af 100644
--- a/util/gflags_compat.h
+++ b/util/gflags_compat.h
@@ -15,6 +15,11 @@
 #ifndef DEFINE_uint32
 // DEFINE_uint32 does not appear in older versions of gflags. This should be
 // a sane definition for those versions.
+#include <cstdint>
 #define DEFINE_uint32(name, val, txt) \
-  DEFINE_VARIABLE(GFLAGS_NAMESPACE::uint32, U, name, val, txt)
+  namespace gflags_compat {           \
+  DEFINE_int32(name, val, txt);       \
+  }                                   \
+  uint32_t &FLAGS_##name =            \
+      *reinterpret_cast<uint32_t *>(&gflags_compat::FLAGS_##name);
 #endif
diff --git a/util/slice_test.cc b/util/slice_test.cc
index 6fea7e622..486590e7b 100644
--- a/util/slice_test.cc
+++ b/util/slice_test.cc
@@ -16,6 +16,13 @@
 
 namespace ROCKSDB_NAMESPACE {
 
+TEST(SliceTest, StringView) {
+  std::string s = "foo";
+  std::string_view sv = s;
+  ASSERT_EQ(Slice(s), Slice(sv));
+  ASSERT_EQ(Slice(s), Slice(std::move(sv)));
+}
+
 // Use this to keep track of the cleanups that were actually performed
 void Multiplier(void* arg1, void* arg2) {
   int* res = reinterpret_cast<int*>(arg1);