If you pay the Upkeep on your Union Crawler in full, the amount of Upkeep you spend goes towards your Upgrade Pool. When the Upgrade Pool reaches the Upgrade Value of your Union Crawler, you may choose to upgrade it. When upgraded, it will boost the Tech Level of Union Crawler to the next Tech Level, and give it all of the new statistics. Many of your Bays will now be able to support wider functions based on the new Tech Level of your Union Crawler, for example, your Crafting Bay may craft anything of its current Tech Level or lower.

You may also spend additional Scrap towards your Upgrade Pool during Downtime if you wish to accelerate the process. However, be careful, as upgraded Union Crawlers cost more Upkeep to maintain.

The upgrade process takes one week. At the end of that week your Union Crawler is upgraded to the next Tech Level. This is intended to make it ready for your next Downtime.