The Catalyst 2980G is actually a fixed-configuration Catalyst 4003 with Supervisor 1 in a small package. The latest software for 2980G (and C4K Sup1) is CatOS 8.1(2) from 05sep03.
Check out the release notes at http://www.cisco.com/univercd/cc/td/doc/product/lan/cat4000/relnotes/ol_4502.htm
End-of-sales hasn't been announced for the 2980G, so the only ones, if any, who can really comment on it's expected lifetime, is your account team.
But you can find more features at a lower price point from other switches (such as the 2950G and 3550), so unless you have specific requirement that mandates the use of a 2980G (CatOS CLI could be one), you should consider the alternatives.
System requirements can also be found in the release notes. 2980G supports 8.1(2) and you need neither a DRAM nor flash memory upgrade.
-A
Asbjoern Hoejmark | CTO | CCIE #8525
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