Specifically, Release 6 (which includes build 15.2.6) introduced several workflow-critical updates:
Users can open, check out, and save documents directly to SharePoint Online. ABBYY FineReader PDF 15.2.6
The "15" series brought significant shifts in how users interact with documents: Specifically, Release 6 (which includes build 15
Unlike older versions that edited line-by-line, version 15 allows text to reflow naturally within blocks, similar to a word processor. similar to a word processor.