Then you are telling me this part does not work ?
To go back to 15.0.1, you have to go to the new download page. That does offer you 15.0.1, to which you're recommended to downgrade. Until tomorrow, when version 16 should be released and you can upgrade the downgrade of your upgrade:
Confused? Sorry about that.
If you haven't yet updated from 15.0.1, you're fine. If you already have version 16.0, grab 15.0.1 from the new link
»www.mozilla.org/en-US/fi ··· fox/new/
and install it over the no-longer-the-newest 16.0.
Once you've downgraded, you'll get another Hooray! page. This time you will be up to date - for a while, anyway.
And if you're not yet on either 16.0 or 15.0.1, you probably need to have a little chat to yourself about updating in general.
Although this latest issue reminds us that it's occasionally problematic to be too far ahead of the curve, it's always risky to be behind.