anchor.diff:  [float]
   === Do not allow stale shards to automatically be promoted to primary (STATUS: ONGOING)
   
  -In some scenarios, after loss of all valid copies, a stale replica shard can be assigned as a primary. This can lead to
  +In some scenarios, after the loss of all valid copies, a stale replica shard can be assigned as a primary. This can lead to
   a loss of acknowledged writes if the valid copies are not lost but are rather temporarily isolated. Work is underway
   ({GIT}14671[#14671]) to prevent the automatic promotion of a stale primary and only allow such promotion to occur when
   a system operator manually intervenes.
  
positive.code: optimizations in Lucene have changed the balance causing the filter cache to
  grow beyond it's size.
  
  While we are working on a longer term solution ({GIT}9176[#9176]), we introduced
  a minimum weight of 1k for each cache entry. This puts an effective limit on the number of entries in the cache. See {GIT}8304[#8304] (STATUS: DONE, fixed in v1.4.0)
  
  Note: this has been solved by the move to Lucene's query cache. See {GIT}10897[#10897]
  
  [float]
  === Ensure shard state ID is incremental (STATUS: DONE, v1.5.1)
  
negative.code: exceptions, but it is still possible to cause a node to run out of heap
  space.  The following issues have been identified:
  
  * Set a hard limit on `from`/`size` parameters {GIT}9311[#9311]. (STATUS: DONE, v2.1.0)
  * Prevent combinatorial explosion in aggregations from causing OOM {GIT}8081[#8081]. (STATUS: ONGOING)
  * Add the byte size of each hit to the request circuit breaker {GIT}9310[#9310]. (STATUS: ONGOING)
  
  