I just read an interesting article about the new licensing on Cisco hardware, especially after the End-of-Sale and End-of-Life Announcement for Cisco IOS Software Release 12.4.
In short the article tells the following:
IOS 12.4 is replaced by IOS 15. IOS 15 is a single software package for the hardware platform that your are using. You have one image with all the features and there’s no need to copy multiple images for different features. By default you can use all the base features and you need a license key to use the Advanced IP feature set.
This licensing can be compared to the licensing of a Cisco PIX, ASA or IPS. Maybe this will be hard for some of you, especially in situations where you replace a broken hardware component (License Transfer Between Two Working Devices).
So pay attention and take some time to dig into the new developments in Cisco IOS 15 licensing.