diff --git a/CHANGELOG.md b/CHANGELOG.md
index f5f7bdf68131527a413b0f66ce6fda01ab4f8e61..07a0075ff018c69017abc408adbdbbf8d9863322 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,13 @@
 # FSL base project changelog
 
 
-## 2111.1 (Fridat 12th November 2021)
+## 2111.2 (Monday 15th November 2021)
+
+* Added the `FSL_GE_606` `Makefile` flag for use by projects which need to
+  retain support for compiling against older versions of FSL.
+
+
+## 2111.1 (Friday 12th November 2021)
 
  - Tweak to how the `-install_name` option is set.
 
diff --git a/config/vars.mk b/config/vars.mk
index 77baee35a09e826189f40274af96bdfdd4eae731..86df5b48cb86d6ba428e143d05f09411e3786cf7 100644
--- a/config/vars.mk
+++ b/config/vars.mk
@@ -7,6 +7,13 @@
 # initialised in the project Makefile.
 #########################################################
 
+# Boolean flag which defines this FSL installation
+# as being from FSL 6.0.6 or newer ("GE" = greater
+# than or equal to). This flag may be used by FSL
+# Makefiles which need to preserve support for
+# older versions of FSL.
+FSL_GE_606 := true
+
 # All projects must specify a name
 PROJNAME =