We have developed a couple of external applications that connect to our Automation Engine systems using the Java Application Interface. In preparation for our upgrade to AE v21, we updated our applications to use uc4.jar v12.3.9. This is the only version of uc4.jar that is able to connect to both v12.3 and v21 systems. (See KB article 232356).
Now, all of our AE systems have been successfully updated to version 12, and it's time for use to begin planning to update our external apps to use uc4.jar v21.
There are some constraints that dictate how we must perform the upgrades:
With these constraints in mind, it became immediately clear that we would have to run dedicated CPs and JCPs in each of the net areas assigned to our external applications. We will therefore follow a staged approach to the migration:
For a while, we will have up wards of 20 (J)CPs running in each AE system. Once the migration is complete, the total number of (J)CPs will go down again.
See also: AWA v21 inter-process communication