BUG in your code

[ghost]

After long long trial and error we finally found the problem. When we updated our records, our DKIM records were cut off ....

In your DnsRecord.PHP class, you use the function substr($value, 0, 200) in setData function.
this cuts off the record at 200 characters ! Major mistake when working with DKIM records which can be considerably longer when using 1024 or even 2048 bit keys !

Solution : Just parse the $value instead of using a substring of it