diff --git a/CHANGES.html b/CHANGES.html
index e83f82431..193c45708 100644
--- a/CHANGES.html
+++ b/CHANGES.html
@@ -63,7 +63,7 @@ us a note on ns-developers mailing list.</p>
 </ul>
 <h2>Changes to build system:</h2>
 <ul>
-<li></li>
+<li>G++ version 8 is now the minimum G++ version supported.</li>
 </ul>
 <h2>Changed behavior:</h2>
 <ul>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4b0efb3d4..c831a75ca 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,9 +26,9 @@ project(NS3 CXX C)
 file(STRINGS VERSION NS3_VER)
 
 # minimum compiler versions
-set(AppleClang_MinVersion 7.0.0)
-set(Clang_MinVersion 3.6.0)
-set(GNU_MinVersion 7.0.0)
+set(AppleClang_MinVersion 11.0.0)
+set(Clang_MinVersion 6.0.0)
+set(GNU_MinVersion 8.0.0)
 
 # common options
 option(NS3_ASSERT "Enable assert on failure" OFF)
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index c582ed689..ff1c37ea6 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -20,7 +20,7 @@ This release is not yet available.
 
 This release is intended to work on systems with the following minimal
 requirements (Note: not all ns-3 features are available on all systems):
-- g++-7 or later, or LLVM/clang++-8 or later
+- g++-8 or later, or LLVM/clang++-6 or later
 - Python 3.6 or later
 - (macOS only) Xcode 11 or later
 
diff --git a/utils/tests/gitlab-ci-clang.yml b/utils/tests/gitlab-ci-clang.yml
index 2cfea125c..bf98d0c49 100644
--- a/utils/tests/gitlab-ci-clang.yml
+++ b/utils/tests/gitlab-ci-clang.yml
@@ -4,7 +4,7 @@
 # "RELEASE", that has a value "weekly". Also, a variable "CLANG" should be set
 # to True.
 
-# We support CLANG 8 - 11
+# We support CLANG 6, 8 - 11
 # The test is done under Linux.
 
 .weekly-build-clang:
@@ -25,27 +25,43 @@
   variables:
     COMPILER: clang++-$CLANG
 
+# CLANG 6
+weekly-build-clang-6-debug:
+  extends: .weekly-build-clang
+  variables:
+    CLANG: 6.0
+    MODE: debug
+
+weekly-build-clang-6-release:
+  extends: .weekly-build-clang
+  variables:
+    CLANG: 6.0
+    MODE: release
+
+weekly-build-clang-6-optimized:
+  extends: .weekly-build-clang
+  variables:
+    CLANG: 6.0
+    MODE: optimized
+
 # CLANG 8
 weekly-build-clang-8-debug:
   extends: .weekly-build-clang
   variables:
     CLANG: 8
     MODE: debug
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python-clang-$CLANG
 
 weekly-build-clang-8-release:
   extends: .weekly-build-clang
   variables:
     CLANG: 8
     MODE: release
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python-clang-$CLANG
 
 weekly-build-clang-8-optimized:
   extends: .weekly-build-clang
   variables:
     CLANG: 8
     MODE: optimized
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python-clang-$CLANG
 
 # CLANG 9
 weekly-build-clang-9-debug:
@@ -53,21 +69,18 @@ weekly-build-clang-9-debug:
   variables:
     CLANG: 9
     MODE: debug
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python-clang-$CLANG
 
 weekly-build-clang-9-release:
   extends: .weekly-build-clang
   variables:
     CLANG: 9
     MODE: release
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python-clang-$CLANG
 
 weekly-build-clang-9-optimized:
   extends: .weekly-build-clang
   variables:
     CLANG: 9
     MODE: optimized
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python-clang-$CLANG
 
 # CLANG 10
 weekly-build-clang-10-debug:
@@ -75,21 +88,18 @@ weekly-build-clang-10-debug:
   variables:
     CLANG: 10
     MODE: debug
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python3-clang-$CLANG
 
 weekly-build-clang-10-release:
   extends: .weekly-build-clang
   variables:
     CLANG: 10
     MODE: release
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python3-clang-$CLANG
 
 weekly-build-clang-10-optimized:
   extends: .weekly-build-clang
   variables:
     CLANG: 10
     MODE: optimized
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python3-clang-$CLANG
 
 # CLANG 11
 weekly-build-clang-11-debug:
@@ -97,19 +107,16 @@ weekly-build-clang-11-debug:
   variables:
     CLANG: 11
     MODE: debug
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python3-clang-$CLANG
 
 weekly-build-clang-11-release:
   extends: .weekly-build-clang
   variables:
     CLANG: 11
     MODE: release
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python3-clang-$CLANG
 
 weekly-build-clang-11-optimized:
   extends: .weekly-build-clang
   variables:
     CLANG: 11
     MODE: optimized
-    EXTRA: libc++-$CLANG-dev libc++abi-$CLANG-dev libomp-$CLANG-dev python3-clang-$CLANG
     
diff --git a/wscript b/wscript
index 5a606b6fe..dd91bedac 100644
--- a/wscript
+++ b/wscript
@@ -33,7 +33,7 @@ examples_enabled = False
 tests_enabled    = False
 
 # GCC minimum version requirements for C++17 support
-gcc_min_version = (7, 0, 0)
+gcc_min_version = (8, 0, 0)
 
 # Bug 2181:  clang warnings about unused local typedefs and potentially
 # evaluated expressions affecting darwin clang/LLVM version 7.0.0 (Xcode 7)