release notes

RELEASE_NOTES.md

@@ -1,7 +1,18 @@
 ## Validator Changes
 
-* no changes
+* Major rework of tx and validation test cases associated with reworking terminology / validator interface and ongoing testing + reconciliation with Ontoserver
+major upgrade to validation - use terminology server to perform more logic, and standardise interface based on agreements with Vocab & Ontoserver
+* Improve slicing error message
+* Add warning to user when referencing an extension that doesn't exist in FHIRPath
+* Fix bugs in FHIRPath implementation of split() and join()
+* Fix bug handling null objects in JSON (R5)
+* Fix for missing search parameter definition in R4
+* fix bug handling XML name extension
 
 ## Other code changes
 
-* no changes
+* Properly populate property definitions in expansions
+* Add CVX Importer
+* R6 release support
+* IPS tool development
+* Improved errors publishing IGs