6.1.0 / 2021-12-07

• feat(populate): support ref on subdocuments #10856
• feat(document): add ownerDocument() method to top-level document for consistency with subdocs #10884 IslandRhythms
• fix: upgrade to mongodb driver 4.2.1 #11032 #10985 lorand-horvath has-n
• feat(schema): support timeseries option for MongoDB 5 time series collections support #10611
• feat(mongoose): add global strictPopulate option #10694 IslandRhythms
• feat(mongoose+connection): add global mongoose.syncIndexes() and Connection.prototype.syncIndexes() #10893 IslandRhythms
• feat(query): support removing fields from projections #10630 canac
• feat(aggregate): add unionWith method to aggregate #10961 saeidasadi
• fix(index.d.ts): types for aggregation pipeline stages #10971 jeremyben