LGTM, many thanks.

Sorry, need to revert it, traceback is:

Traceback (most recent call last):
File "./update-gpg-keys", line 179, in
keyinfo = get_keyinfo(f)
File "./update-gpg-keys", line 89, in get_keyinfo
p = Popen(cmd, stdout=PIPE, stderr=PIPE, encoding='utf-8')
TypeError: init() got an unexpected keyword argument 'encoding'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "./update-gpg-keys", line 181, in
print('Failed to get keyinfo for %s: %s' % (f, e.strerror))
AttributeError: 'TypeError' object has no attribute 'strerror'

The encoding argument to Popen() is available in Python 3.6, you probably have an older version. But if we need to support 3.5 I can do it.

We need to be able to run this script on any local machine which has at least F25. We can exclude Python versions which were in F24 because it's EOL, but these are scripts we use to update the key blocks, so it doesn't matter if we then will support 3.5, 3.6 or more.
You are right, I have F25 with 3.5.3, probably we should support from that version upwards.
Thank you for your patience.