There appears to be different types of dungeons and players have no way of knowing the type when entering. It would be nice if the type of dungeon was clearly indicated prior to entering a dungeon. This is pretty important info, and I think it confuses and frustrates lots of players.
Type 1 Dungeon Any friends of any level can enter with you on sigils or port in.
Type 2 Dungeon Any friends can enter with you on sigils, but no porting in late.
Type 3 Dungeon Only friends that actively have the quest (or completed it) can join you on the sigils.
Type 4 Dungeon Nobody can join you. Its a Solo dungeon.
I despise that moment when you are in a dungeon at the last battle and you think, hmm this boss looks hard, I am gonna ask my friends for help. They say they can't port.
With RottenHearts idea, we will know when to ask for help
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level 84