We are currently using webM 7.1.2 and want to migrate to webM 8.0.
My question is what level of code changes is required to migrate to webM 8.0

My guess is that minimal to No change are required to just port the IS packages, - Please correct me if I am wrong.

Also is there a list of issues resolved in webM 8.0 which was a problem in the earlier version and developers either had to live with it as a product limitation or did a work around.

SoftwareAG has already release a upgrade guide which explains all required steps for “Upgrading from 7.1.2 to 8.0 SP1 - Overinstall”. You can download it from [url]http://techcommunity.softwareag.com/ecosystem/documentation[/url]

Overinstall is a approach where your existing Integration server will be directly upgraded to wm 8, and you shouldn’t require any code level changes of setting up any parallel infrastructure.

Following URL is talking about the new features/functions of wm 8:

http://techcommunity.softwareag.com/ecosystem/documentation/webmethods/wmsuite8_ga/relnotes/8-0_webMethods_Release_Notes.html