USCIS just posted newly revised instructions for people who are filing the I-751, the application to remove conditions on residence. You can read the full press release from USCIS here.
The press release indicates that one files either with the Caifornia Service Center or the Vermont Service Center depending on residence and to use the newest I-751 form — available at their website. All of this effective immediately.
The I-751 is typicalled filed by those who initially achieved status through marriage to a US citizen. The status initially given is “conditional” — after two years, then one applies to get “regular” permanent residence (the greencard). It’s important not to forget about the second step.