On my 7.1 version I had an Island that will place an ad between the first and the second post for each thread.
I did the update and this feature is gone. I can't find where I do the setting for that.
The Island that control it still there available on my island, but it's not showing.

Any ideas?
Thank you

That's located in the 'forum details' page, custom inserts tab:

Custom Island Insert
This will show up between the 1st and 2nd post of a topic. Usually the most effective place to put ads.

Answering my own question:

Now you have to go to Forum Permissions, select the Forum you want show that ad, (one by one) and give the "Must View Ad Island" permission to each member of that forum that you want to see that ad.
Also, you have to prepare before hand like AllenAyres wrote on the post above (thank you Allen).
I hope it helps another users.