With the introduction of the Mercury Performance System in earlier versions, 12.1.0.56 added specific optimizations for:
While the core features of InDesign CC 2017 were established in version 12.0, the 12.1.0.56 update brought crucial refinements:
Object Styles received a much-needed upgrade in this version. Designers could now define "Object Size & Position" within a style. This allowed for auto-positioning of objects (like a logo that must always be 10mm from the top right corner) and auto-sizing text frames, significantly speeding up repetitive layout tasks. Adobe InDesign CC 2017 12.1.0.56
The build number 12.1.0.56 is critical because it addressed many of the frustrations from the initial 12.0 launch. Based on Adobe’s release notes (archived), key fixes included:
Note for archivists: Version 12.1.0.56 is often considered the “golden build” of the CC 2017 line because later 12.x.x patches introduced minor regressions that were only fully resolved in CC 2018. With the introduction of the Mercury Performance System
While you legally needed a CC subscription in 2017, many perpetual licenses were sold for this version at the very end of Adobe's "perpetual" transition. If you hold a genuine serial number for 12.1.0.56, you can run this software offline indefinitely without monthly payments.
This was arguably the most impactful feature of the CC 2017 lineup. InDesign 12.1 allowed deep integration with Creative Cloud Libraries. Designers could: Note for archivists: Version 12
The CC 2017 release introduced several paradigm-shifting features that streamlined the creative process.