How do I upgrade encrypted devices to Lollipop - Moto G, Dell Venue 7?

[Richter915]

How do I upgrade encrypted devices to Lollipop - Moto G, Dell Venue 7

Hi all,

To access one of my email accounts I had to encrypt my phone and tablet. The email system updated and now I no longer need to have my phone encrypted. Because my phone is encrypted, it seems that I can't perform an OTA upgrade to lollipop and it's driving me mad. Any time I go to system update it says that my system is already up to date.

I have a Moto G (1st gen) running on KitKat 4.4.4

I have a Dell Venue 7 3730 running on KitKat 4.4.2

What should I do? I thought about decrypting but it seems that, unlike Samsung, my systems don't provide a straightforward way of doing it. There is a factory reset option which I know works but I want to backup both of my systems as best as possible before trying that. Are there any other ways I can decrypt my devices?

One issue with the Venue 7 is that I can't find a set of compatible USB drivers anywhere so connecting it to my PC has been a problem.

Thanks!