# Cal.com v6.1.15 — Release & Upgrade Intelligence
- **Product:** Cal.com (https://cal.com)
- **Version:** v6.1.15
- **Released:** Feb 12, 2026
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/calcom/updates/v6.1.15/

## Executive Summary (TL;DR)
Cal.com v6.1.15. Source highlight: chore: resolve @modelcontextprotocol/sdk to 1.26.0

## New Features
- feat: refactor billing to strategy implemention
- feat: add claude specs
- feat: caretta.so app
- feat: add UTM parameter data to insights bookings CSV download
- chore: add agent rules to prevent circular dependencies between packages
- feat(form-builder): format field labels to display human-readable names

## Improvements
- perf: optimize getBusyTimesForLimitChecks with batched parallel queries
- perf: use UNION ALL with DISTINCT for bookings query optimization

## Bug Fixes
- fix: update booking page terms text to use APP_NAME instead of "our"
- fix: add i18n + migration for booking history pbac
- fix: API v2 `@GetWebhook()` decorator doesn't generate OpenAPI path
- fix: renamed `rediss://` to `redis://`  in .env.example
- fix: hide cancel/reschedule links in emails when disabled
- fix: use randomString() for booking UIDs in slots E2E tests