[JKT]

Release candidate means that a developer believes that the software is now bug-free in-so-far as it is possible, but will not declare it so until a further round of testing has been completed. If further bugs are identified then a second, third, fourth etc RC will be released. Strictly speaking you shouldn't really see more than a couple of RCs at most as that implies that the 'RC' wasn't bug-free enough to be given the designation.

Therefore, RC means that the developer is fairly sure that this is the version that will be released as the final version of that update, but is putting it through one final round of testing before declaring it so (if no more serious bugs are identified).