That sounds like a major, incredibly dangerous update to the DB driver. Their 7.1, 7.2, 7.3 versions seem to all have breaking changes [1].
Yet they are in obvious violation of SemVer expectations, which they declare to follow [2]:
> Mongoid follows versioning guidelines as outlined by the Semantic Versioning Specification, so you can expect only backwards incompatible changes in major versions [sic]
Yet they are in obvious violation of SemVer expectations, which they declare to follow [2]:
> Mongoid follows versioning guidelines as outlined by the Semantic Versioning Specification, so you can expect only backwards incompatible changes in major versions [sic]
[1] https://docs.mongodb.com/mongoid/current/tutorials/mongoid-u...
[2] https://mongoid.github.io/old/en/mongoid/docs/upgrading.html