Sharing my limited API skills. Below script can be used to query logs API for the Endpoint VPN Client version used over the last 30 days into a json formatted file 'vpnclientversion.json'
You need R80.40 JHF Take 78 or later to use Logs API (link)
# Login as admin apiUser to query Logs API
mgmt_cli login user "apiUser" password "vpn123" > sessionID.txt
# show logs
echo "show logs" 2>&1 | tee -a sessionlog.out
/bin/date 2>&1 | tee -a sessionlog.out
mgmt_cli set session new-name "show VPN Client Versions" description "show VPN Client Versions" -s sessionID.txt
mgmt_cli show logs new-query.time-frame "last-30-days" new-query.filter "blade:\"Mobile Access"\" -s sessionID.txt --format json > ./vpnclientversion.json
echo "All done.." 2>&1 | tee -a sessionlog.out
/bin/date 2>&1 | tee -a sessionlog.out
mgmt_cli logout -s sessionID.txt
Then you can use jq to see the client versions found per logs message.
cat vpnclientversion.json | jq -r '["client_name","client_version"], ( .logs[] | .client_name as $clientname | .client_version as $clientversion | [$clientname, $clientversion] )'
This is far from perfect but may help.
-pelmer