• [CHANGE] Reject invalid external URLs at startup. #1960
• [CHANGE] Add Fingerprint to template data. #1945
• [CHANGE] Check Smarthost validity at config loading. #1957
• [ENHANCEMENT] Improve error messages for email receiver. #1953
• [ENHANCEMENT] Log error messages from OpsGenie API. #1965
• [ENHANCEMENT] Add the ability to configure Slack markdown field. #1967
• [ENHANCEMENT] Log warning when repeat_interval > retention. #1993
• [ENHANCEMENT] Add alertmanager_cluster_enabled metric. #1973
• [ENHANCEMENT] [ui] Recreate silence with previous comment. #1927
• [BUGFIX] [ui] Fix /api/v2/alerts/groups endpoint with similar alert groups. #1964
• [BUGFIX] Allow slashes in receivers. #2011
• [BUGFIX] [ui] Fix expand/collapse button with identical alert groups. #2012