The issue that you are experiencing is caused by the new firmware which corrected a non-CiA conform handling of the PDO mapping. In order to allow changing the PDO mapping, the CiA conform way is to disable the PDO mapping first, by writing a 0x00 into the Index 0x1A00, subindex 0x00! However, there is another issue that prevents the user from writing to any subindex 0x00 as these are considered "read-only" in CoEdit! In order to be able to write to that subindex you will need a new CoEdit version, as the previous version per default did not allow writing to any subindex = 0x00!

Attached is a temporary CoEdit version, which allows you to write to the subindex 0.
NOTE: This version has not been released officially. But in order to be able to change the Object Dictionary entry 0x1A00 subindex 0x00 this version is necessary.

Also Attached is the firmware that is necessary to be flashed onto the M01! (firmware version must be >= v1.10r0)

Step by step:
1) write value 0 to index 0x1A00, sub 0x00
2) change PDO mapping as described in the M01 manual, e.g.:
write 0x91300220 to index 0x1A00 sub 0x02 (map temperature as int32)
write 0x00AC0000 to index 0x6131 sub 0x02 (set degree F as temperature unit)
3) write value 0x02 to index 0x1A00, sub 0x00 (this will write-protect the PDO mapping again)
4) write the "save" command:
write ASCII value "save" to index 0x1010, sub 0x01
‚s’ = 0x73, ‚a’ = 0x61, ‚v’ = 0x76, ‚e’ = 0x65