Backward Compatibility Tracker

Philosophy

Full Calendar Remastered (FCR) is committed to zero-friction upgrades. This document tracks all active legacy support logic, its location in the codebase, and the rationale for maintaining it.

Active Legacy Support

Feature / Migration	Supported Since	Code Location	Rationale
Timezone Auto-Upgrade	ea817059	feat(arch): Implement provider architecture, multi-account support, and notifications
ICS Path Polymorphism	6606ff5	feat: ActivityWatch FSM sync + continuity rewrite, provider identity diff, settings UX, and Tasks integrations (#142 #166 #175) (#238)
Google OAuth Migration	ea817059	feat(arch): Implement provider architecture, multi-account support, and notifications
Bulk Categorization Tool	c6017712	feat(workspace): add customizable calendar workspaces with filtering, UI, and performance improvements (#90)
Stable Source IDs	c6017712	feat(workspace): add customizable calendar workspaces with filtering, UI, and performance improvements (#90)
Category - Title Parsing	v0.10.0	(Legacy feature supporting the Category - Title naming convention)

Retired Support (Breaking Changes)

• v0.10.0: Removed support for the calendar: name key in frontmatter in favor of directory-based source identification.
• v0.12.0: Removed legacy resourceTimeline view support if Advanced Categorization is disabled (sanitizes to timeGridWeek).

Maintenance Policy

1. Detection: Legacy data should be detected at the "Read/Load" boundary.
2. Reparation: Whenever possible, the plugin should perform a "Lazy Upgrade" (upgrading data only when it is modified by the user).
3. Deprecation Notices: Before retiring any support, a console warning and 3-month lead time in the Changelog is required.

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