Google Analytics 4 launched in October 2020, initially branded as "Google Analytics 4 properties" to distinguish it from Universal Analytics. Google released it as an early-access beta before making it the default option for new properties in late 2020. The rollout happened in stages. From October 2020 to June 2022, GA4 ran parallel to Universal Analytics, letting site owners choose which version to implement or run both simultaneously. Google announced in March 2022 that Universal Analytics would stop processing data on July 1, 2023 for standard properties (July 1, 2024 for Analytics 360). That sunset deadline forced the industry-wide migration we saw through 2022–2023. GA4 represented a fundamental architecture change, not just an update. It moved from session-based tracking to event-based tracking, introduced cross-platform measurement combining web and app data, and built machine learning into core reporting. The shift caused significant friction because GA4 eliminated many Universal Analytics reports and metrics that marketing teams relied on daily. At Ottawa SEO, we started testing GA4 implementations in early 2021 for our portfolio sites and began migrating client properties in mid-2022, well before the deadline. Running dual tracking for 12+ months gave us historical data in both systems for comparison and helped identify reporting gaps early. The timing matters for historical data access. If you didn't set up GA4 before July 2023, you have zero pre-migration data in the new system. Universal Analytics data remains accessible in read-only mode until July 2024 (now expired for most properties), but Google provided no automatic data transfer between platforms. For Canadian businesses especially, the October 2020 release date is relevant for compliance tracking. Quebec's Law 25 and federal PIPEDA considerations apply to how GA4 handles user data, and properties launched after the GA4 release should have implemented it with privacy controls from day one rather than scrambling during the 2023 migration rush.