Plotly 4.x to 5.x migration: Figure dict schema and layout template compatibility

Maintaining Visual Consistency Across Plotly Versions

Updating a production application from Plotly 4.x to 5.x introduces changes to the figure dictionary schema, specifically regarding default layout templates and modebar visibility settings. When migrating existing figures that rely on implicit defaults, there is a risk of rendered output shifting visually or losing specific UI elements upon deployment.

To ensure a zero-downtime transition, the application must handle these schema shifts without breaking existing Dash callbacks or altering the end-user experience. This requires a strategy for reconciling the 4.x default state with the 5.x template system.

• How can the figure dictionary be normalized to ensure identical rendering of the modebar and layout templates across both versions?
• What is the recommended approach for explicitly defining templates to prevent 5.x from overriding legacy 4.x visual defaults?