error updating qubes-template-centos-7

[Adam Mercer]

Hi

I'm trying to update the centos-7 template, installed from the
community templates repo, using the Qubes Update utility and the
process is failing with:

Updating centos-7

Error on updating centos-7: Command '['sudo', 'qubesctl',
'--skip-dom0', '--targets=centos-7', '--show-output', 'state.sls',
'update.qubes-vm']' returned non-zero exit status 20
centos-7:
----------
_error:
Failed to return clean data
retcode:
1
stderr:
Traceback (most recent call last):
File "/var/tmp/.root_dd8a91_salt/salt-call", line 27, in <module>
salt_call()
File "/var/tmp/.root_dd8a91_salt/pyall/salt/scripts.py",
line 437, in salt_call
import salt.cli.call
File "/var/tmp/.root_dd8a91_salt/pyall/salt/cli/call.py",
line 6, in <module>
import salt.cli.caller
File
"/var/tmp/.root_dd8a91_salt/pyall/salt/cli/caller.py", line 14, in
<module>
import salt.loader
File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader.py",
line 7, in <module>
import contextvars
File "/var/tmp/.root_dd8a91_salt/py3/contextvars.py", line
1, in <module>
from _contextvars import Context, ContextVar, Token, copy_context
ModuleNotFoundError: No module named '_contextvars'
stdout:

How can I enusre then the template is updated?

Cheers

Adam