Some FLUID template variables have been renamed to be less generic. If you use your own templates, you have to adapt them accordingly.
The classic rendering method has been removed.
As of version 1.3.2, the classic rendering method is deprecated. It will be removed in version 2.0.0.
Version 0.3 introduces the cObject rendering method for the placeholder. This method is enabled by default and uses a FLUIDTEMPLATE cObject for rendering and XLIFF language files for localization.
If you changed the default wraps or texts in your installation, this may be a breaking change. Use the Constant Editor to disable cObject based rendering.
You should consider adapting your installation to the new rendering, as the classic rendering method will be deprecated in a future version.