If you want to stay within the law my understanding is that you need to distribute patches against decompiled Skype rather than decompiled Skype with patches ap

If you want to stay within the law my understanding is that you need to distribute patches against decompiled Skype rather than decompiled Skype with patches applied, otherwise you're distributing a derivative work. This may still be a legal grey area though. IANAL, you ANAL, we all ANAL and that.