Sometimes WordPress Toolkit does not detect plugin updates: inside WordPress Toolkit there are no newer versions, but inside WordPress dashboard newer version of a plugin is shown. Or vice versa: WordPress Toolkit shows an update, but the plugin page itself does not detect it inside WordPress admin dashboard.
WordPress Toolkit checks for the update using the native wp-cli utility. It interacts with a plugin to detect newer versions. So the versions are shown in WP Toolkit and the ones in the standard WP plugin update dashboard (WordPress > Plugins page) should match.
The plugin page itself may not show any information about the update or show some version that WordPress itself could not detect if the plugin uses a different update mechanism (for example, a paid plugin can do so) standard WordPress utility may not detect this update or plugin itself does not see it since it is using different update procedure. In both cases, contact plugin vendor is required.
It is possible to check plugin updates via CLI with the command like below:
# plesk ext wp-toolkit --wp-cli -instance-id INSTANCE_ID -- plugin status
3 installed plugins:
UI akismet 4.1.6
I hello-dolly 1.7.2
Legend: I = Inactive, D = Drop-In, U = Update Available
Note: To get the instance ID, the following command can be used:
# plesk ext wp-toolkit --list