Update README.adoc
diff --git a/README.adoc b/README.adoc
index 670e76e..d49a9c6 100644
--- a/README.adoc
+++ b/README.adoc
@@ -1,10 +1,10 @@
// XX to be filled in by the merger of this PR (likely Jon)
-= *Advance Notice of Pending XML Registry Change (posted 2020-11-XX)*
+= *Advance Notice of Pending XML Registry Change (posted 2021-01-XX)*
[WARNING]
.Warning
====
-Shortly after 2021-02-XX, we will be removing the old-style group blocks
+Shortly after 2021-04-XX, we will be removing the old-style group blocks
(contained within the `groups` section at the top of the XML registry)
The groups are intended to contain all the possible legal values
for corresponding function parameters, but it is likely that many
