I’m upgrading to a 4.2.7 board and need to know which firmware for an E3 Pro with BLTouch 1.3and Micro/swiss Direct Drive, Also how does one connect the BL Touch as currently it’s connected to the Z-stop and an adapter board into the display socket on a 1.1.5 board…
Hi @fullbore and welcome to the forums.
Usually you will find on the downloads page for your printer various different firmwares. You will want to make sure the one you download is for the 4.2.7 board and will also want to make sure that bl touch or cr touch is in the filename too.
Generally when fitting a bl or cr touch probe the z stop is disconnected/removed as the probe takes over the job of the end stop switch.
Hope that helps 
Nothing at
Mentions 4.2.7 and BLTouch though.
My guess is that you would need the Ender-3Pro_HW4.2.7_SW2.0.9.03_SpritExt_H300 firmware but as you are using a third party hotend you may need to make adjustments as necessary.