&gt;I don&#x27;t use for-loops, because a while-loop can do the same, and it&#x27;s too hard for me to learn.<p>Pretty much. Older engineer. He remembers the transition from blackberry to Android and is not ready for another one. He almost advocates for the use of Vectors ...<p>Unfortunately he is also Lead Engineer, which makes matters complicated. Kotlin is far from the only subject where we butt heads. I also had to put his nose on all the leaks created by his atrocious &#x27;architecture&#x27; in order to start working on a fix.<p>I don&#x27;t think there is a good solution for that kind of problems other than throwing the towel and move to another company. I plan to emigrate anyway, so there is that.<p>There are true reasons to avoid Kotlin at the moment though :<p>-slower compilation (we have a huge codebase and dexing is already an issue).<p>-the whole team needs to move to it and since we are more than a dozen, it is a significant task.<p>-Kotlin does not support Android Lint, so common issues like using an API 21 method with minApiLvl = 17 can occur unnoticed.