People are being scared off by the experimental status on
https://gcc.gnu.org/projects/cxx0x.html
e.g. https://gcc.gnu.org/ml/gcc/2015-10/msg00025.html
This makes it clear C++11 in 5.1 is no longer experimental.
We also have a "Standard Conformance" section for G++ in
https://gcc.gnu.org/bugs/ which says "Two milestones in standard
conformance are GCC 3.0 (including a major overhaul of the standard
library) and the 3.4.0 version (with its new C++ parser)." I've
added some more recent milestones, although maybe std::lib conformance
doesn't need to be mentioned in this context?
Index: htdocs/projects/cxx0x.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/projects/cxx0x.html,v
retrieving revision 1.67
diff -u -r1.67 cxx0x.html
--- htdocs/projects/cxx0x.html 26 Jan 2015 11:12:43 -0000 1.67
+++ htdocs/projects/cxx0x.html 6 Oct 2015 10:58:01 -0000
@@ -28,10 +28,10 @@
line. GCC 4.7 and later support <code>-std=c++11</code> and
<code>-std=gnu++11</code> as well.</p>
- <p><strong>Important</strong>: GCC's support for C++11 is still
+ <p><strong>Important</strong>: Before GCC 5.1 support for C++11 was
<strong>experimental</strong>. Some features were implemented based on
- early proposals, and no attempt will be made to maintain backward
- compatibility when they are updated to match the final C++11
+ early proposals, and no attempt was made to maintain backward
+ compatibility when they were updated to match the final C++11
standard.</p>
<h2>C++11 Language Features</h2>
Index: htdocs/bugs/index.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/bugs/index.html,v
retrieving revision 1.116
diff -u -r1.116 index.html
--- htdocs/bugs/index.html 5 Jul 2014 21:52:32 -0000 1.116
+++ htdocs/bugs/index.html 6 Oct 2015 10:58:01 -0000
@@ -696,9 +700,12 @@
However, some non-conforming constructs are allowed when the command-line
option <code>-fpermissive</code> is used.</p>
-<p>Two milestones in standard conformance are GCC 3.0 (including a major
-overhaul of the standard library) and the 3.4.0 version (with its new C++
-parser).</p>
+<p>Significant milestones in standard conformance are
+GCC 3.0 (including a major overhaul of the standard library),
+the 3.4.0 version (with its new C++ parser),
+4.8.1 (complete C++11 language support),
+5.1 (complete C++14 language support),
+and 5.1 (complete C++11 and C++14 standard library support).</p>
<h4>New in GCC 3.0</h4>
