Beta 26 is newer than Build 4 and if you're using Beta 26 you should not downgrade back to Build 4. Aside from Build 4 lacking features that Beta 26 has, and Build 4 having more bugs than Beta 26, Build 4 also uses an older version of the database and I believe that a downgrade will cause some issues on top of that.
In short: if you're using Bet 26, keep using Beta 26 until Beta 27 comes out in a few days (at which point the new features in Beta 27 are going to be good enough that you'll likely want to upgrade anyway
.