Hi Folks!
There's a special paragraph about the availability of upgrades in the
5.2 beta announcement:
There will be NO upgrades from 5.1.10 to 5.2 Beta - as long as it's in Beta.
There WILL BE upgrades from 5.1.x to 5.2.x, when a stable release of v.5.2 is available
There WILL BE upgrades within branch 5.2 Beta and from Beta to a stable version