If you are choosing a version today, understand these critical differences:
Because it contained no breaking changes from earlier 2.3.x versions, it became the default "safe upgrade" for production systems. Many Data Engineers still refer to bokeh 2.3.3 as "the last great classic Bokeh." bokeh 2.3.3
This script outputs a fully interactive HTML file. Notice how no web server or JavaScript is required. If you are choosing a version today, understand
Previous versions occasionally crashed when rendering >100,000 points with WebGL acceleration. Bokeh 2.3.3 included a backported fix for MultiGlyph rendering, drastically reducing memory leaks in long-running applications. User guide — Bokeh 2
If you are upgrading from 2.3.3 to 3.x, consult the Migration Guide as version 3.0 introduced significant changes to the layout engine and property system. User guide — Bokeh 2.3.3 Documentation
Users can define their own "properties-only" subclasses to share data across different parts of an application more efficiently.