Updating Deprecated Blender Addons To Work With New Versions
Finding Outdated Add-ons in Your Blender Installation
Using the Add-on Info Panel to Check Versions
The Add-on Info panel in Blender’s user preferences provides detailed information on all add-ons currently installed. This includes the add-on name, author, version number, and a description. Checking this can quickly identify any add-ons that are outdated and in need of updating.
Specifically, look for add-ons with version numbers that do not match the latest releases. Most good add-on authors properly version and date their releases. You can cross check sites like BlenderMarket or Gumroad to find the most up-to-date version.
Pay special attention to any add-ons that mention they work withspecific older Blender versions like 2.79 or 2.80. These are very likely to cause errors or fail completely in newer releases like 2.91 or 2.92 unless updated.
Identifying Deprecated Python Code
In many cases, opening up the Python code of an add-on directly can reveal deprecated functions, methods, and API calls. These stand out by raising warnings and exceptions in Blender’s console or Info view.
For example, common messages are:
- “Deprecated: Module bpy.types.Scene.render is deprecated”
- “Deprecated: bpy.context.scene.render.filepath is deprecated”
Seeing warnings like this suggest the code needs updating to work properly in the latest Blender versions. The messages usually mention exactly what needs to change.
Updating the Code for Compatibility
Changes to the Blender API Over Versions
A major reason old add-ons break is because the Blender Python API continually evolves across new releases. Method names, import paths, and entire modules get renamed, moved or removed completely.
For example in Blender 2.80, the entire RenderEngine API was revamped. Many rendering related properties were moved out of the Scene data into a new ViewLayer data structure.
Add-ons that touch areas like rendering, modifiers, or workflows heavily customized in new Blender versions are most likely to be affected.
Common Areas That Need Updating
Some specific areas that commonly need updating are:
- Import/Export Helpers – Changes to importers and exporters like for FBX, glTF etc.
- Render Properties – Path changes like bpy.context.scene.render to bpy.context.view_layer
- Modifiers – Renamed enumeration values like MOD_SUBSURF to MOD_SUBSURF_CATMULLCLARK.
Reading the release notes and upgrade documentation for each newer Blender version can guide you on which areas have changed.
Example Code Snippets for Key Changes
Here is an example of updating deprecated Scene render properties from the old API:
import bpy
# Old API
render = bpy.context.scene.render
filepath = render.filepath
# New API
import bpy
import os
render = bpy.context.scene.render
render_filepath = os.path.dirname(bpy.data.filepath)
if not render_filepath:
render_filepath = bpy.context.preferences.filepaths.render_output_directory
And swapping to the new ViewLayer:
# Old API cycles = bpy.context.scene.cycles # New API view_layer = bpy.context.view_layer cycles = view_layer.cycles
With some tweaking to account for API and naming shifts like this, most add-ons can be updated to run in newer Blender versions.
Testing and Troubleshooting Your Updated Add-on
Using Blender’s Console for Debugging
Once you’ve gone through and updated any deprecated code in your add-on script, it’s essential to thoroughly test it before releasing a new version.
Blender provides an integrated Python console that outputs errors and warnings right inside the app itself. This should be your main tool for troubleshooting issues.
Common things to test are:
- Enabling the add-on via User Preferences
- Checking its panels/menus appear in the interface
- Trying all its tools/features for errors
Pay close attention to error messages in the console, and fix any areas of code triggering exceptions.
Fixing Errors and Issues
Sometimes an update may seem to work fine initially but then show errors later during normal usage. Extensive testing is key to catch these.
It can take some trial and error adjusting pieces of code until deprecated functions are properly replaced. Using search engines to get examples helps enormously here.
Be methodical and patient in correcting Python errors thrown – explain the first reported line, then go from there.
Verifying Correct Functionality
Besides just fixing crashes/errors, you need to validate your add-on works 100% properly in all its features. Re-download the old version and do comparisons if needed.
Some things to check:
- Interface looks pixel perfect
- Tools/buttons work
- Operators perform accurately
- Modifier parameters function
Don’t finalize your updated add-on until you are fully satisfied with how it looks and performs after the changes made during the compatibility update.
Distributing Your Updated Add-on
Sharing on Blender Community Platforms
Once your add-on passes all tests and works properly in modern Blender versions, it’s time to push out the updated release for others to enjoy!
The Blender Market and Blender Nation platforms have huge existing user bases always seeking properly maintained add-ons.
It is well worth posting your updated work there for free or as a paid asset. Follow their listing guidelines, provide plenty of pictures/videos showing it in action, and be responsive to any user feedback or issues reported.
Creating a Proper Release Package
For distributing your add-on, first package up the final updated Python scripts along with any other auxiliary files like documentation, images, samples etc.
Use a clear version-based naming convention like My_Addon_2.3.zip so users can easily identify the release.
Make sure you include a README file that shows the exact Blender versions supported, requirements, installation instructions, and change log highlighting updates.
Licensing Considerations
If you offer your updated Blender add-on publicly, be sure to include a proper open source license like GPLv2 or Creative Commons.
This makes clear to users what is allowed in terms of sharing/modifying your work for their own purposes.
Choose a license wisely depending on how “open” you want the add-on’s downstream usage to be, and if/how you require attribution.
