An old Cisco 4700 router, rock solid but nevertheless approaching the end of its useful life, needs to be replaced. It's configured with three modules: dual Ethernet, 8 port BRI, and balanced E1, and handling a2 MBit/s E1 Internet connection with ISDN backup and (nowadays rarely used) dialin either via ISDN or an analog modem on the aux console port. The IOS image it runs is the IP Plus IPSec 3DES feature set because it also terminates a couple of LAN2LAN IPSec tunnels.
What would be the appropriate replacement? A 2811 with an NM-8B-S/T and a VWIC-1MFT-E1 would nominally bring the same number of interfaces. Will it provide the same functionality? Which IOS feature set will I need?