The most significant "interesting feature" introduced in Adobe InDesign CC 2017 (version 12.1.0.56) is the support for spanning footnotes across multiple columns.
Help troubleshooting common issues like font weight display errors in this version. Let me know which specific area you'd like to explore next! How to obtain InDesign 2020 / 15.1? - Adobe Community Adobe InDesign CC 2017 12.1.0.56
This specific point release (12.1.0.56) focused on streamlining the design workflow and integrating tighter connections with Adobe’s broader ecosystem: Hyperlink Performance : The engine for checking hyperlinks
Hyperlink Performance: The engine for checking hyperlinks in external documents was refined, significantly speeding up the Hyperlinks panel in long documents. What's New with InDesign CC 2017 - CreativePro Network including font styles
Cannot move or edit text boxes in InDesign 2021 - Adobe Community
Released in early 2017 as part of Adobe’s Creative Cloud continuous release cycle, InDesign CC 2017 version 12.1.0.56 is a stable update to the professional page layout software. This build primarily focused on bug fixes, performance improvements, and refinements to features introduced in the initial CC 2017 release (12.0).