update documentation

Author: web-flow

docs/lnd/release-notes/release-notes-0.19.0.md

@@ -78,6 +78,11 @@
   initial historical sync may be blocked due to a race condition in handling the
   syncer's internal state.
 
+* Add support for [archiving channel backup](https://github.com/lightningnetwork/lnd/pull/9232)
+ in a designated folder which allows for easy referencing in the future. A new 
+ config is added `disable-backup-archive`, with default set to false, to 
+ determine if previous channel backups should be archived or not.
+
 ## Functional Enhancements
 * [Add ability](https://github.com/lightningnetwork/lnd/pull/8998) to paginate 
  wallet transactions.
@@ -220,6 +225,9 @@
   added and they will be removed in a future release. The defaults values for 
   these options have also been increased from max 3 log files to 10 and from 
   max 10 MB to 20 MB. 
+
+* Refactored the `ValidationBarrier` to use
+  [set-based dependency tracking](https://github.com/lightningnetwork/lnd/pull/9241).
 
 * [Deprecate `dust-threshold`
 config option](https://github.com/lightningnetwork/lnd/pull/9182) and introduce