diff --git a/BUILDING.md b/BUILDING.md
index f76c571..08f004c 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -31,8 +31,10 @@
     `CMAKE_ASM_NASM_COMPILER`.
 
   * C and C++ compilers with C++11 support are required. On Windows, MSVC 14
-    (Visual Studio 2015) or later with Platform SDK 8.1 or later are supported.
-    Recent versions of GCC (4.8+) and Clang should work on non-Windows
+    (Visual Studio 2015) or later with Platform SDK 8.1 or later are supported,
+    but newer versions are recommended. We will drop support for Visual Studio
+    2015 in March 2022, five years after the release of Visual Studio 2017.
+    Recent versions of GCC (6.1+) and Clang should work on non-Windows
     platforms, and maybe on Windows too.
 
   * The most recent stable version of [Go](https://golang.org/dl/) is required.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5dcd8ce..6a5a6aa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -117,7 +117,7 @@
 if(CMAKE_COMPILER_IS_GNUCXX OR CLANG)
   # Note clang-cl is odd and sets both CLANG and MSVC. We base our configuration
   # primarily on our normal Clang one.
-  set(C_CXX_FLAGS "-Werror -Wformat=2 -Wsign-compare -Wmissing-field-initializers -Wwrite-strings -Wvla")
+  set(C_CXX_FLAGS "-Werror -Wformat=2 -Wsign-compare -Wmissing-field-initializers -Wwrite-strings -Wvla -Wshadow")
   if(MSVC)
     # clang-cl sets different default warnings than clang. It also treats -Wall
     # as -Weverything, to match MSVC. Instead -W3 is the alias for -Wall.
@@ -172,11 +172,6 @@
   if(CLANG)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wmissing-prototypes")
   endif()
-
-  if(CMAKE_COMPILER_IS_GNUCXX AND "4.8" VERSION_GREATER CMAKE_C_COMPILER_VERSION)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-array-bounds")
-  endif()
-
 elseif(MSVC)
   set(MSVC_DISABLED_WARNINGS_LIST
       "C4061" # enumerator 'identifier' in switch of enum 'enumeration' is not
@@ -254,12 +249,6 @@
   add_definitions("-D_STL_EXTRA_DISABLED_WARNINGS=4774 4987")
 endif()
 
-if((CMAKE_COMPILER_IS_GNUCXX AND CMAKE_C_COMPILER_VERSION VERSION_GREATER "4.7.99") OR
-   CLANG)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wshadow")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wshadow")
-endif()
-
 if(CMAKE_COMPILER_IS_GNUCXX)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c11")
 endif()