Today I deployed what should be the last update to the Power TAC server before a release we plan for the end of next week (16 March 2019). Unless one of us has time to address Issue #853 in the next 3-4 weeks, this will be the version we use for the 2019 tournament. There are no major functional changes and no API changes from the 1.5.0 version used in the 2018 tournament, so a broker that worked well in 2018 should be competent to enter in the 2019 Power TAC tournament (here is the CfP).
We will have full release notes ready with the release. The significant changes you will see in comparison with version 1.5.0 include (1) a major increase in the capacity of the WindmillCoOp and SolarLeasing models (the capacity of the SolarLeasing model should be restored to what we saw in the 2017 tournament); (b) a correction in the payments for regulation capacity; and (c) more realistic behavior for the electric vehicle model, which are now not always plugged in when not driving, and offer somewhat more regulation capacity when they are plugged in. Details will be in the release notes.
Please try out the current 1.6.0-SNAPSHOT server and let us know if you have concerns or questions. We hope to see your brokers entered in the 2019 tournament this summer.