Did you read the error message and try to understand it or perhaps the meaning was not obvious?
Fatal error: Uncaught exception 'Httpful\Exception\ConnectionErrorException' with message 'Unable to connect to "http://arastta.io/core/1.0/update/1.6.2/5.6.26/5.5.57-cll"
This part suggests a time lag with your Internet connection or the server you were trying to connect to (this is a quick guess).
However, you may need to download Arastta ver 1.6.2 from "GitHib" "https://github.com/arastta/arastta/releases" to see the differences. It may be possible to manually update it yourself. It can only be files and database changes or possibly just one or the other? Arastta may confirm this or do a file and database difference check (lots of developer tools are capable of this function, sometimes called file compare too).
We have just tested the update and it was successfully updated. I would also check server permissions on your files on your server in case this is the cause. With your error message saying it could not connect it may be unlikely, but is often a problem.
We wouldn't recommend using the new version on a clients site without first testing it. Wait and see if any glaring errors show up before considering using it.
Always backup before any major updates too.
If you download both Arastta ver 1.6.1 and Arastta ver 1.6.2 from https://github.com/arastta/arastta/releases.
Then extract both versions and do a directory and file comparison (you can also compare the contents of the files themselves).
Then do a clean install of both versions, preferably in the same environment (done seperately), to avoid even any path differences being confusing in the comparison.
If you have Control Panel access and PHPMyadmin you can export the MySQL database (it's only a text file) and either carefully look for differences or again use an application designed for or with a feature for file comparison.
This way you avoid any custom data you may later add confusing the comparisons at this stage.
Developer editors like Atom or Komodo Edit are free and can help here.
Looks to be like the same thing with us as well. It seems to be like on Arastta end with their server.... Would love to get this back up and running!