What IP are you referring to? Copyright? The software stack (kernel, GNU, X, Qt etc) is Free Software. Trademarks? The MeeGo trademark belongs to the Linux Foundation. Patents? Jolla would be no more or less vulnerable than any other company in this space (modulo that Nokia has granted a patent licence to the Linux kernel), so any suit targetted at a small startup of ex-employees would likely be seen as vexatious and thrown out immediately.