There were several firmware improvements over time, that improved (reduced) the transmit/receive changeover click. With 1.07a you get all those improvements.
The only hardware change that reduced clicks was the C21 and C22 changing from 10uF to 1uF.
I do recommend this change. We use 1uF ceramics (MLCC) in the QCX+ and QCX-mini kits but any types will be OK. Lower capacitance values would be OK too but that does increase the attenuation. The QCX has plenty of gain but I wouldn't go much below 1uF. For example 0.47uF would be not too bad if you don't have 1uF.
73 Hans G0UPL--
73, Bernie, VE3FWF
(most typos in this message have been generated by highly sophisticated auto-correction software)