Mongo 4.2+ now supports sharding key value change. Doctrine - doesn't.

[o10g]

Feature Request

Doctrine now supports sharding key value change.
There are some limitations, but nothing critical.
The major one - you must provide sharding key in a "where" clause in case you change it.

https://docs.mongodb.com/manual/core/sharding-shard-key/#change-a-document-s-shard-key-value

Nowadays doctrine just unsets the sharding key changes on update if it knows about sharding. Or it just doesn't have any way to modify the query for "where" clause.

Q	A
New Feature	yes
RFC	no
BC Break	yes

Summary

Sharding key value change for Mongo 4.2+.