If you already downloaded the AL Player's Guide and AL DMs Guide, there have been some nice little changes. Please download them again. I'm providing links to the files on DMsGuild. If you get them from there, then they will notify you if there are any other updates.

AL Player's Guide (5.1)
AL DM's Guide (2.1)

As I mentioned before, ditch the old ones, including past seasons. They are superseded by these.

Updates to my previous post:
  1. I had mentioned that the concept of Story Origins were being removed, but we were keeping the PHB+1 Rule. You can have the PHB and one additional sourcebook for your character. However, this does NOT apply to Backgrounds. Any Background from any AL-allowed Source can be used, even if it's not your +1. In addition, you can make up your own background using the rules in the PHB.
  2. A small change to the trading rules now that certs are no longer required: Each player will have to expend 15 Downtime Days to trade. This includes from one of your character to another one. The only exception to this expenditure is if you are in an adventure with the other character you are trading with. (Which of course doesn't help trading between your own characters, since you can't play both at the same time.)
  3. The gods have heard your pleas regarding the complete character-ending finality of Disintegration. You miss a save, you roll a new character. Kind of harsh. Resurrection and True Resurrection have both been added to the downtime spellcasting services list. But let me warn you. It's pretty steep. Actually it's very steep. Let's just say, you want to make your save, or use an Inspiration, or buy the DM some Sour Skittles or something.

PS: Don't actually try to bribe your DM. Buy him some Sour Skittles because he works hard bringing you enjoyment week to week to week. At least before he zapped your character, anyway.

Play on.