Upgrading 3 year old Unity 5.6 Vuforia based project...where to start?

Game not working properly when upgrading from 3.5 V to 4.3 V of unity 1 Answer

Where do I put PlayerPrefs.SetInt? 1 Answer

camera/minimap problem on upgrading to unity 5.4.2 1 Answer

Will i need to buy anything for upgrading unity 4 0 Answers

"Unable to instantiate prefab. Prefab may be broken" 7 Answers