MongoDB 2.6.8-rc0 is out and is ready for testing. This is a release candidate containing only fixes since 2.6.7. The next stable release 2.6.8 will be a recommended upgrade for all 2.6 users.
Fixed in this release:
SERVER-17087 Add listCollections command functionality to 2.6 shell & client
SERVER-16599 copydb/clone commands can crash the server if a primary steps down
SERVER-16274 Secondary fasserts trying to replicate an index
SERVER-15802 Query optimizer should always use equality predicate over unique index when possible
As always, please let us know of any issues.
— The MongoDB Team.