Will upgrading a Nexus 4 to Android 5.0 require a "reset"

My Nexus 4 has been bugging me that a new Android is available, since a few weeks. However, I read somewhere that upgrading would make me lose my data and have to re-install everything. Is that really the case ? (I find it strange that it would be so insistent, if it were true that this causes loss of data/setup).