Mongoid 7.5.4 is a patch release in the 7.5 series, addressing the following issues:

• MONGOID-5642 Queryable::Selector#merge! does not properly handle :$in/:$nin keys
• MONGOID-5643 Storable#add_field_expression add values with same operator keys using $and when value is a hash with symbol operator key

The following issue was also done, affecting only a clean-up of old documentation:

• MONGOID-5648 Remove release notes for archived versions