Crashes on iOS 10.2.1 all the time!!

Game is great when it does not crash. Crashes consistently when using pokémon go plus and also regularly. What is the deal! also add:

quests
ability to fight each other
mysterious ultra rare items that dont come on your 7th pokestop spin. Stop giving in to the teenagers who want instant gratification !!

Beoygm about Pokémon GO, v1.27.4