XmrSubscriber - Process Message :: Unopenable Message : unknown block type

Am sending command via API. I was able to send CMS version 1.8.8, but after upgrading 1.89 getting this error on client. Is there any change on API?

No, however the unknown block type, most likely means that the keys are out of sync.

If you would navigate to the Displays page -> Edit display -> Advanced tab -> Reconfigure XMR & Save
On the next collection interval (or after you restart the player) it should regenerate the keys which should solve the XMR issue.

Thanks, I did as you told. After restart it works again.
Edit: I try another player, it also need to reconfigure xmr. Do we need reconfigure xmr everytime, after cms update?