Upgrading from Universal Analytics (UA) to Google Analytics 4 (GA4) isn’t a simple ‘upgrade’ – it requires setting up a new property and running it alongside your existing UA property. UA stopped processing new hits on 1 July 2023, but as of December 2025, GA4 is the standard Google Analytics platform for all new data collection.
GA4 operates on a fundamentally different data model than UA. UA is session-based, tracking interactions within a defined timeframe, while GA4 is event-based, recording every user interaction as a distinct event. This means GA4 now includes features like enhanced measurement, automatically tracking events like page views, scrolls, outbound clicks, site search, video engagement and file downloads without requiring custom code. Data retention settings in GA4, as of December 2025, allow for data to be kept for up to 14 months in the free version, with longer retention options available through Google Marketing Platform integrations. Australian businesses should be aware of Google’s data processing agreements, which comply with Australian Privacy Principles. GA4’s machine learning capabilities are continually expanding; in 2026, these will now include predictive metrics like churn probability and purchase probability, offering insights into user behaviour. The GA4 interface differs significantly from UA, focusing on lifecycle reporting – acquisition, engagement, monetisation, and retention.
GA4 functions by collecting data through a JavaScript tag (gtag.js) or Google Tag Manager, sending event data to Google’s servers for processing and reporting, providing a more flexible and privacy-centric approach to web analytics.
