We currently have a Cisco 1841 router with version 12.4(1c) of IOS using image c1841-ipbase-mz.124-1c.bin. Our goal is to make it so our router can fully support IPv6. The current IOS version cannot. I've seen a site that seems to indicate 12.4T does support with IP Base image but recently had Cisco tell me with the latest IOS release 15.1.4.M4 that I have to use either the "Advanced Enterprise Services" or "Advanced IP Services" image. Did Cisco just remove IPv6 from IPBase in later IOS releases?
Also I've seen conflicting specs on the max amount of Flash and DRAM the router can support. The following link shows that 384MB is the max for DRAM and 128MB max for flash. We're looking to upgrade ours from 128MB and 32MB respectively but as mentioned I've seen it where higher amounts are supported. In fact we bought a backup 1841 to have and it has a 256MB Flash card in it.
Last but not least. Where can I find a straightforward documention of this situation where we may have to upgrade our Flash and DRAM and then upgrading the IOS?