To tell which device you have, use the Roku interface to navigate to Settings- About where the model is listed.
These devices are not compatible with the latest Hulu app and are therefore losing access to the streaming platform altogether.
Roku devices affected by this are already running the "classic" Hulu app, which has a number of limitations compared to the regular app, including a lack of live TV and inability to receive content from some premium channels. After June 24th, users of those models might see error messages, won't have the ability to sign in or may see the app vanish entirely.
Hulu is not the first streaming service to stop supporting older Roku devices; Netflix stopped working on some Roku devices previous year because they didn't support the DRM that Netflix now uses.
Hulu is still committed to Roku's newer streamers but requires that your Roku device be updated to at least version 8.1 of the company's OS. The players were limited to using the "classic" Hulu app versus the modern one.
By ensuring the firmware is up-to-date, Hulu is promising "access to new features and all of the content that you subscribe to" will continue.
When Netflix ended support for old devices, it was a more severe cull and included the Roku SD, Roku HD, Roku HD-XR, Roku XD, and Roku XDS. In that case, older Roku devices - plus older Samsung and Vizio products - could not support the DRM (digital rights management) now used by Netflix. Older gamers could keep streaming video indefinitely, however publishers pushing for upgraded DRM is a most likely cause behind streaming services like Hulu and Netflix phasing them out.
The new version of the app lets users get to their destinations with fewer clicks.