So we are looking at upgrading one of our 7206VXR NPE-G1s to 12.2(33)SRD4 from 12.2(31)SB17. We duplicated the production router in the lab running the SB(17) code. Then we upgraded to the SRD4 code and compared the configs. It seems the no auto-summary command has been removed from all of the address-family ipv4 vrfs. I should point out that the default behavior is not to summarize and it isn't summarizing, but the option to enable it isn't there either. I can't see any time when we would want to turn it on but I can't find any documentation saying when that command was removed or changed and it bothers me. I'm still looking but thought I would throw this out there in case someone had a quick reference. There are a lot of release notes to read.
The behavior has been changed in the current IOS.
"The MPLS VPN Per VRF Label feature does not support auto-summary."
The behavior was modified under vrf address-families because, unlike aggregate-address command, auto-summarization does not install a summary route on the router where summarization is performed. This may lead to scenarios where mpls label switched paths can break. So the cli has been modified to prevent auto-summary configuration under vrf address-families and default behavior is 'no auto-summary' for vrf address-families.
The workaround is to use aggregate-address for BGP summerization under vrf address-families.