I've stumbled across a setting for this (though I've not used the community much before the update). Found in Community>My Settings>Preferences You will see another 'tab': >Linear Layout There, there is a checkbox to "Jump to first unread post in a t...
I've done this - changed my number online - but noticed that it would not do it, initially, when my account was not paid-up. It was useful, and I took my time to look through lots of numbers, and got one with 5 repeating digits (easy to remember!).