A upgraded AS to 3.0 Beta 1 and my Kotilin plugin to 1.2-M2-release-Studio3.0-1 and changed my Kotlin version in gradle to 1.2-M2. However, I get an event saying "Outdated Kotlin Runtime, you version of Kotlin runtime in 'kotlin-stdlib-1.2-M1"..." . Any idea what other config I need to update?

most likely you have another dependency that pulls in 1.2-M1