Differences in firmware version numbers

dog-man wrote:Why is the v20 firmware for 0585162 Uk unbranded black = v20.0.019.209.07

And 0570817: RM-505_EMEA_EURO_QW1 Black = v20.0.019.C01.01?

Why the different firmware numbers?

Is there any difference in the actual content available on the phones?

All numbers after the initial 20.0.019 relate to country and network variants.
Depending on the network involved (if not a generic product code), there may be Operator specific content with some variants.
The main firmware file 20.0.019 is identical on ALL Euro product-codes (maybe even identical globally).