Worked on the nextcloud/android repository to enhance calendar interoperability by addressing a bug related to ICS event formatting. Focused on aligning the Android calendar module with RFC 5545 standards, the work involved implementing compliant formatting for calendar events, including accurate DESCRIPTION fields, unified time zone handling with TZID Europe/Berlin, and consistent event durations. The update also ensured the removal of unnecessary blank lines and preserved the complete VTIMEZONE block, improving compatibility across Nextcloud, Google Calendar, and iOS clients. Utilized Java for Android development and calendar integration, demonstrating attention to protocol compliance and cross-platform reliability in calendar data exchange.