Pureos won't update

No, it isn’t, wait and run apt update again within next few days until you get apt list --upgradeable message. For now you might consider to type within your terminal following:

sudo apt autoremove
sudo apt autoclean
sudo shutdown -hF now

“Unable to get list of updates”, probably current one, message within/from gnome-software is not something related to PureOS or its repository, IMO.

I still cant get PUREOS to update. I tried to install signal by whisper systems but it wouldnt work. Now I get
Sorry something went wrong:
E: Type ‘sudo’ is not known on line 1 in source list /etc/spt/sources.list.d/signal-xenial.list

nothing loads when i launch software app. L can select a menu from categories but then theres nothing in there, in any of them.
Im unable to delete the signal from the authentication list.

Any ideas?

If you didn’t use this method, perhaps this helps:

sudo snap remove signal-desktop

In short, might depend on used method (how) when signal-desktop was installed, but please don’t mix Debian and Ubuntu addresses within the same sources.list (never ever).

Snap isnt recognised.

Can signal be run on PureOS? I thought I had it running about a year ago.