Invisibility has been in the code a potion effect for some time now, however it does not currently (In 1.3.1/1.3.1) have an effect nor can you access it without making an item with a mod. With them adding Night Vision in the last snapshot, as well as adding Haste and Jump Boost (Maybe I missed some) I would say they are finally going to be finishing off the potions that have not been used. They could also be finishing these so they can add more in the future. You never know with them.
Having difficulty updating, the client keeps freezing at random places before it is fully downloaded anyone else getting this?
Do you have an anti-virus like AVG or something similar. If so you will have to temporarily disable it. I used to have the same problem some time ago until I spent about 35 minutes looking for how to fix this.
Rare? Just because you never go to the nether (apparently) doesn't make a bug rare...
Shoulda checked the 1.3.1 thread, to see just how common these two bugs were.
Maybe if you whined less you would have heard about those bugs?
While this update might be valuable to you, keep in mind that there are others who see that this 'update' is too lacking to be called as such. I for one have never experienced this falling out of the Nether out of the 2 dozen or more times that I've been there. I would know, since set up a zombie pigman farm to collect gold. I might have been just lucky, however.
I'm not gonna complain about the bug fixes you focused on. I'm sure a lot of people were experiencing those issues. And as I pointed out in my most recent thread, "I don't experience the problem, therefore it doesn't exist." is terrible logic. However, I hope you all haven't forgotten about the big pulsating FPS bug that's still hanging over our heads. I feel this is just as important as the issues you corrected in this update. It makes the game a lot slower for a lot of people, and unplayable for a few.