TeX Live Utility on Mac OSX error: installing gpg appears to have failed

Question

I am trying to update my current version of TeX on Mac OS X 10.15.7. I don't think I've ever updated it before but I was told that to use my university LaTex thesis template, I should install "Tex Live 2021" or update the package using Tex Live Utility.

First, I went to https://www.tug.org/texlive/ where it says

... for MacOSX, see the MacTeX distribution.

So I went to this link and started downloading the MacTeX Download (which takes over 30 mins).

Then I read here that you can use something called the TeX Live Utility on Mac.

However, when I open this app it asked me if I want to do security checks on packages so I said 'yes' and then after a long wait I get this error:

I also tried updating it this way:

tlmgr update --all

and

tlmgr update --self

both produce this error:

/Library/TeX/texbin/tlmgr: open tlpdb(https://ctan.mirror.rafal.ca/systems/texlive/tlnet/tlpkg/texlive.tlpdb) failed: No such file or directory at /usr/local/texlive/2018/tlpkg/TeXLive/TLPDB.pm line 362.

So I guess I have 2 questions:

1. Which of the two methods is the right way to update TeX language on Mac OS X (launching the downloaded MacTex package or using Tex Live Utility)?
2. If the latter, what is the problem with my TeX Live Utility above?

Answer 1

I think I have solved the problem. The solution is quite obvious in retrospect:

1. From the Tex Live Utility menu select 'Check for updates' - this updated my app to the latest version (1.49). It then immediately reported that my MacTex version is out of date and opened a browser on the MacTex download page.

2. I downloaded the latest MacTex distribution (MacTeX-2021 April) and installed the package.

3. Re-open TeX Live Utility and select the updates tab. This immediately opens a dialog saying 'Critical updates available'. Press update button.