Open your steam library
Right click on Valheim
Select properties
Click on the Betas menu
Click the drop down menu from the top box
Select default_old - previous stable version

Get in contact with your friend and let him know he needs to update. If you have been playing on a server the server admin needs to update to the newest version. If you aren't the server admin/owner you have to wait until they do so or until the server auto updates.

Some companies that provide server hosting are slow with the updates. If you complain they usually give you free time or a discount.

The above has happened to me a few times. It usually gets updated within 24-48 hours.

as you can see from above i did just that. and not just once, i went through that routine with 5 different charaters in varied stages with in the game hoping that i didnt have one who would trigger the old/new version and not happening.this took a long time switching versions and trying to join with each one, one at a time. plus closing/opening the game after each version and characters. and still nothing changed

Having the same issue, but I am the host, and my Valheim isnt showing it needs any updates..

EDIT: Youll need to make sure that both you and your host are using the same version. If you are on the public beta, they will need to be as well or you both wont be on the same version! Check the latest update on the main page for info :D

i understand this. and know this wasn't my first time in his game or him in mine. but after the last update this has changed and i had hoped someone might know what i can do to get this fixed.
i have 4 different characters in different stages of the game.
1 has been to the mistlands pre-mistland update
1 never been passed the dark forest
1 never gone pass the plains
1 thats been all over the mistlands

now i went and backed up the save files then started going through each of the available versions with each of these, which took a awful long time, and got the same message after trying to join each time.
then i made a completely new character and again tried it out on all of the versions and yet still got the same message

i didn't come to the forms half hearted or unprepared. i did go the full extent of what i could on my end and the streamer even tried joining my hosted game to no avail as he had received the same message.
however this is another reason for coming here as we had someone else new to the game have no problem joining his game what so ever.

so in the end i'm still left with no answer or clue as to what i'm going do to fix this problem