At the time of this writing, the latest Gradience Pro/Enterprise version is 11.0.1606.29.
The 16 refers to the year 2016.
The 06 refers to the month of June.
The 29 refers to the day-of-the-month.
As you are reading this, we may have moved up to a newer version but the logic of our version numbers remains the same. You can find your full, multi-digit version number by opening the software and clicking Help > About.
If you're running a version older than 11.0.1605.10 of Gradience Pro / Enterprise, you [MUST] use Firebird 1.5 as your database engine.
If you are running version 11.0.1605.10 or version 11.0.1606.29, you may use Firebird 1.5 or Firebird 2.0.7. as your database engine.
If you are running a version newer than 11.0.1606.29, you [MUST] use Firebird 3.0 as your database engine.