I have established that the cause of my sdk-version errors is the dexer.
In one link here Erel said that we must set the MaxRamForDex=0 in the .ini file. Then it was established that it cannot be set to zero, and Erel promised to make the next update to accept 0 (in 2013).
More lately we are advised to set it at 1024 (2018).
When I set it to zero, these errors disappear, but a new error springs up as below:
Generating R file. (2.19s)
Compiling debugger engine code. Error
Invalid maximum heap size: -Xmx0m
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
PK