Will this build number work?

DL 2019 from my trainz portal. Build # is 105096 Will this cause any problems building and uploading routes to the dls?

No problems with this build as it is build 4.6, like all of TRS19 prior to SP2 beta.

As long as the asset build number of the routes and sessions you create are build 4.6 or less, then there will be no problems or complaints about your creations working in TRS19 SP1 and TRS19 PE SP1. TRS19 SP2 (in the various versions) will create routes and sessions with asset build numbers of 4.7