It looks like there is an update coming for the Android G1 which should be pushing out sometime at the end of January. It will be pushed one region at a time and deliver Cupcake elements to the G1. There was speculation that this would be released on January 15th but now there is confirmation that while it did not release yesterday it is still coming soon.
From Google and Blog:
FACT – There WILL be a G1 update shortly as it was INTENDED to be by mid-January so the next target is now by the end of January.
FACT – T-Mobile will not just provide Cupcake elements to the G2 and leave the G1 behind.
FACT – The next update will be called RC31 and include Cupcake elements.
FACT – The mass of calls lately for Cupcake is registering and causing T-Mobile to double their efforts in getting the update out.
FACT – NO ONE has received RC31 as of today.
FACT – When the update is released it will be done in stages “Over The Air” but it will be by region not when you purchased the G1.
FACT – The memo I was privy to is NOT distributed to Support personnel.
FACT – T-Mobile Specialists & Support are LAST to know when an update happens and are notified AFTER it is released as was the case with RC29 & RC30.
FACT – T-Mobile does have a battery improvement program in motion
FACT – T-Mobile’s plan for battery improvement will be one of OR a combination of efficiencies in an OTA update and an extended life battery replacement.