I'm also seeing "Mandatory Upgrade to Litecoin 0.8.6.1+." everytime I start Junkcoin-qt. Anyone have a solution? I have already upgraded my litecoin wallet but still see this message in Junkcoin.
This is an issue that many altcoin clients have/had. The devs did not change the key for broadcasts and hence are listening to messages sent on the Litecoin network. This is fairly simple for devs to fix in the client.
It's a little annoying but will not affect the operation of the client whatsoever.