The Service Pack 2 baseline has been dropped and SP3 is now required to install Office 2007 updates from this point forward.

Why?

Please see the Microsoft Support Lifecycle pages for full details. Here’s a quick summary – once a Service Pack is released, support for the previous baseline ends 12 months after release (or at
the end of the product lifecycle, whichever comes first) for Office products. Since we are now a year past the release of SP3, we have reached the end-of-life for the SP2 baseline.

Builds with check-in to drop RTM baseline:

QFE Build: 12.0.6672.5000 (February CU build – CP2)

COD Build: 12.0.6670.5004

 

What this means:

Any patches from the builds noted above, or later, will no
longer apply over the SP2 baseline. SP3 must be installed in order to apply
future updates.

 

First customer releases which will contain this change:

February PU, February CU 2013

 

FAQ:

Q: What about products that didn’t have an SP3 release?

A: For any products which fall into that category, the last
released baseline is still the most current baseline, so will continue to be
supported.