3.0? 1.2? Confusing docs?

Do “Zigbee 3.0” devices need a 3.x Zigbee router firmware ?

Should the ‘supported devices’ list not include this information if so ? I cannot get many new devices to work at all currently on a 1.2 firmware (Hue smart button, SmartThings socket).

There’s reference to there being “no benefit at the moment” to a v3 firmware over a v1.2. Is this true?

What’s the difference Between firmwares “CC2531ZNP-with-SBL.hex” and “CC2531ZNP-without-SBL.bin” ? What is SBL? Why is one the binary and another a hex dump? What is the ‘patch’ for ?

Is the pairing story the same? I couldn’t get a 3.0.x firmware to pair anything with my CC2531 - is that because I ought to have been sending it a ‘allow pairing’ message because this times out after a short while?