MultiGet should not fail entirely if alias resolves to many indices #20858 (issue: #20845)
Fixed date math expression support in multi get requests. #20659 (issue: #17957)
Cluster
Remove cluster update task when task times out #21578 (issue: #21568)
Reenable shard management on IndicesClusterStateService #20741
Core
Binary fields indexed into an upgraded (from 1.x → 2.x) index hit "Compressor detection can only be called on some xcontent bytes or compressed xcontent bytes" exception #21440 (issue: #11280)
Protect BytesStreamOutput against overflows of the current number of written bytes. #21174 (issue: #21159)
StoreStatsCache should also ignore AccessDeniedException when checking file size #20790 (issue: #17580)
Index APIs
Only negate index expression on all indices with preceding wildcard #20898 (issues: #19800, #20033)
Java API
Null checked for source when calling sourceRef #21431 (issue: #19279)
Plugin Cloud Azure
Fix logger when you can not create an azure storage client #20669 (issue: #20633)
Query DSL
Fix NPE when parsing InnerHits with highlight query #21065 (issue: #21061)
Stricter parsing of multi_match "query" parameter #20884 (issue: #20785)
Fix match_phrase_prefix query with single term on _all field #20471 (issue: #20470)
REST
The routing query string param is supported by mget but was missing from the rest spec #21357
Read indices options in indices upgrade API #21281 (issue: #21099)
Search
Max score should be updated when a rescorer is used #20977 (issue: #20651)
Make range queries round up upper bounds again. #20582 (issues: #20579, #8889)