The most common problem that I am seeing on the aliases this morning is folks who are running 151a with a support update finding that their upgrade is failing.
The reason for this is that the version of pkg that you need to do the upgrade is in SRU#13. You need to update to this before switching to the release repository and upgrading.
This is an absolutely required step.
If you have an SRU older than #13 and have already switched to the release repository, you will need to switch back to the support repository, update and then go back to the release repository.