Mark 2.11 as an LTS release

CHANGELOG.txt

@@ -1,8 +1,8 @@
 Changelog
 =========
 
-2.11 (xx.xx.xxxx) - IN DEVELOPMENT
-~~~~~~~~~~~~~~~~~
+2.11 LTS (xx.xx.xxxx) - IN DEVELOPMENT
+~~~~~~~~~~~~~~~~~~~~~
 
  * Add support for aliased pages (Karl Hobley)
  * Add support for hierarchical/nested Collections (Robert Rollins)

docs/releases/2.11.rst

@@ -7,6 +7,9 @@ Wagtail 2.11 release notes - IN DEVELOPMENT
     :depth: 1
 
 
+Wagtail 2.11 is designated a Long Term Support (LTS) release. Long Term Support releases will continue to receive maintenance updates as necessary to address security and data-loss related issues, up until the next LTS release (typically a period of 12 months).
+
+
 What's new
 ==========