Possibly as far back as 2021.12, the string value of "none" is not allowed for a sensor entity that has a device class of timestamp. This will cause an exception. This change leaves the value as None (which results in "unknown", instead of changing it to the invalid value of "none".)
Fixes #82
Possibly as far back as 2021.12, the string value of "none" is not allowed for a sensor entity that has a device class of timestamp. This will cause an exception. This change leaves the value as None (which results in "unknown", instead of changing it to the invalid value of "none".)