arti config missing proxy target type

built arti 1.1.13 to test onion services

attempt to start up arti, using arti config for 1.1.12. arti would not start:

./arti_1.1.13: error: read configuration: Config contents not as expected: Could not parse proxy target type.

I cannot find, in documentation, a "proxy target type" mentioned.

arti --help or arti proxy --help are not useful.