While is a highly-rated, open-source factory automation game, there is no official version 1.5.6 . The latest stable release provided by the developer on the Official GitHub is v1.5.1 , which introduced official mod support.

If you are looking for the "newest" features in the series, you may be interested in the sequel, , which is currently in active development and includes: Wires Update - Shapez.io

: Beyond level 26, the game enters a "Freeplay" mode where throughput goals must be met and processing speeds can be upgraded infinitely (up to Tier 1000).