The following table shows the removed items:
| Item | Notes | Type |
| copyDb clone |
Command | Copies an entire database. Although this command is still available, you cannot use it to copy a database managed by a mongod version 4 instance to one managed by a mongod version 3.4 or earlier instance. Use the external binaries mongodump and mongorestore instead after upgrading to MongoDB 4. |
| db.copyDatabase() | Mongo shell command | This is a wrapper for the copyDb command. The same notes for copyDb clone apply. |
| db.cloneDatabase() | Mongo shell command | This is a wrapper for the clone command. The same notes for copyDb clone apply. |
| geoNear | Command |
Reads geospatial information (that is, latitude and longitude) and returns documents in order, based on their proximity to the source point. Instead of this command, in MongoDB 4.x, you would use the $geoNear aggregation stage operator or the $near or $nearSphere query operators, depending on the nature of the query... |
