ProEXR 2.0 beta for After Effects adds support for Cryptomatte
Open source plugin ProEXR 2.0 is currently in development and a beta is now available for testing. The update adds support for Cryptomatte to the After Effects plugin, enabling users to decode masks that are created automatically using compatible renderers (including Clarisse, Arnold, Mantra, Redshift and V-Ray). The beta installer is available to download by following the links in the Decoders section of the Cryptomatte GIT repository.
Source: CG Channel