* Treat TransportService stopped error as node is closing {pull}39800[#39800] (issue: {issue}39584[#39584])
* Use cause to determine if node with primary is closing {pull}39723[#39723] (issue: {issue}39584[#39584])
* Don’t ack if unable to remove failing replica {pull}39584[#39584] (issue: {issue}39467[#39467])
* Fix NPE on Stale Index in IndicesService {pull}38891[#38891] (issue: {issue}38845[#38845])
Engine::
* Advance max_seq_no before add operation to Lucene {pull}38879[#38879] (issue: {issue}31629[#31629])
Features/Features::
* Deprecation check for indices with very large numbers of fields {pull}39869[#39869] (issue: {issue}39851[#39851])
Features/ILM::
* Correct ILM metadata minimum compatibility version {pull}40569[#40569] (issue: {issue}40565[#40565])
* Handle null retention leases in WaitForNoFollowersStep {pull}40477[#40477]
Features/Ingest::
* Ingest ingest then create index {pull}39607[#39607] (issues: {issue}32758[#32758], {issue}32786[#32786], {issue}36545[#36545])
Features/Monitoring::
* Don't emit deprecation warnings on calls to the monitoring bulk API. {pull}39805[#39805] (issue: {issue}39336[#39336])
Features/Watcher::
* Fix Watcher stats class cast exception {pull}39821[#39821] (issue: {issue}39780[#39780])
* Use any index specified by .watches for Watcher {pull}39541[#39541] (issue: {issue}39478[#39478])
* Resolve concurrency with watcher trigger service {pull}39092[#39092] (issue: {issue}39087[#39087])
Geo::
* Geo Point parse error fix {pull}40447[#40447] (issue: {issue}17617[#17617])
Highlighting::
* Bug fix for AnnotatedTextHighlighter - port of 39525 {pull}39750[#39750] (issue: {issue}39525[#39525])
Infra/Core::
* Allow single digit milliseconds in strict date parsing {pull}40676[#40676] (issue: {issue}40403[#40403])
* Parse composite patterns using ClassicFormat.parseObject {pull}40100[#40100] (issue: {issue}39916[#39916])
* Bat scripts to work with JAVA_HOME with parantheses {pull}39712[#39712] (issues: {issue}30606[#30606], {issue}33405[#33405], {issue}38578[#38578], {issue}38624[#38624])
* Change licence expiration date pattern {pull}39681[#39681] (issue: {issue}39136[#39136])
* Fix DateFormatters.parseMillis when no timezone is given {pull}39100[#39100] (issue: {issue}39067[#39067])
* Don't close caches while there might still be in-flight requests. {pull}38958[#38958] (issue: {issue}37117[#37117])
Infra/Packaging::
* Use TAR instead of DOCKER build type before 6.7.0 {pull}40723[#40723] (issues: {issue}39378[#39378], {issue}40511[#40511])
Infra/REST API::
* Update spec files that erroneously documented parts as optional {pull}39122[#39122]
* ilm.explain_lifecycle documents human again {pull}39113[#39113]
* Index on rollup.rollup_search.json is a list {pull}39097[#39097]
MULTIPLE AREA LABELS::
* metric on watcher stats is a list not an enum {pull}39114[#39114]
Machine Learning::
* [ML] Fix datafeed skipping first bucket after lookback when aggs are … {pull}39859[#39859] (issue: {issue}39842[#39842])