You may be affected by this bug when the sorted sets you use contain integer members in the 24-bit signed range (+/- ~8 million). If the 2.6 RC server already took writes to these sorted sets, they may be corrupted (contain duplicates).
Nothing to worry about. You're good to go!
If possible, use the original 2.4 dump, upgrade the 2.6 RC process to the code listed below, and restart Redis loading the dataset from the 2.4 dump.
Upgrade the 2.6 RC process to the code listed below, restart the 2.6 RC instance, and let it re-sync with the 2.4 master.
- Repository: https://github.com/pietern/redis/tree/2.6-zipfix
- Issue report: redis/redis#500