Update ANNOUNCEMENT file

Add remoteauth as a new overlay
Add deprecated backend section and adjust backends accordingly
Mark wired tiger backend as experimental

ANNOUNCEMENT

@@ -22,7 +22,7 @@ A N N O U N C E M E N T -- OpenLDAP 2.5
             - Sun/Netscape draft persistent search support
             - HAProxy proxy protocol v2 support
         * New backends
-            - back-wt: Wiredtiger backend to slapd
+            - back-wt: Wiredtiger backend to slapd (Experimental)
             - back-asyncmeta: Async version of back-meta
         * Backend updates
             - back-ldap: CANCHAINOPS
@@ -31,14 +31,16 @@ A N N O U N C E M E N T -- OpenLDAP 2.5
         * Retired backends
             - back-bdb
             - back-hdb
+            - back-shell
+        * Deprecated backends
             - back-ndb
             - back-sql
             - back-perl
-            - back-shell
         * New overlays
             - autoca
             - homedir
             - otp
+            - remoteauth
         * New password hashing module
             - argon2
         * Overlay updates