4400X needs upgrade to continue playing Hulu. Per Hulu app.
Hulu says it wrote the current version of its Roku channel app to be compatible with the following Roku models, running Roku operating software version 11 or higher. Older Roku models not on this list are no longer supported by Hulu. If your older Roku model is not on this list, you'll need to replace it with a supported model in order to receive Hulu.
You can check your Roku model and model number via Roku menu path Settings > System > About. Presumably newer models not yet listed by Hulu will also work. (This information is current as of June 1, 2023. For updates, see the link below)
Roku 2 (4210X)
Roku 3
Roku Streaming Stick (3600X, 3800X), Stick+, 4K, 4K+
Roku Express, Express+, 4K, 4K+
Roku Premiere, Premiere+
Roku Ultra, Ultra LT
Roku Smart Speaker
Roku TV, 2K, 4K, 8K
Source: https://help.hulu.com/s/article/supported-roku
Hulu says it wrote the current version of its Roku channel app to be compatible with the following Roku models, running Roku operating software version 11 or higher. Older Roku models not on this list are no longer supported by Hulu. If your older Roku model is not on this list, you'll need to replace it with a supported model in order to receive Hulu.
You can check your Roku model and model number via Roku menu path Settings > System > About. Presumably newer models not yet listed by Hulu will also work. (This information is current as of June 1, 2023. For updates, see the link below)
Roku 2 (4210X)
Roku 3
Roku Streaming Stick (3600X, 3800X), Stick+, 4K, 4K+
Roku Express, Express+, 4K, 4K+
Roku Premiere, Premiere+
Roku Ultra, Ultra LT
Roku Smart Speaker
Roku TV, 2K, 4K, 8K
Source: https://help.hulu.com/s/article/supported-roku
Roku has ceased support for the Roku 4 (4400). It was the first 4K player and has a unique CPU and other items that are NOT shared with other models. It's up to developers if they want to continue supporting it. Disney, which controls most of Hulu, has decided to drop support for both Hulu and Disney+. Apple TV was NEVER supported.
If you don't need Ethernet, the Express 4K+ is a good replacement. It's faster and has more internal storage memory for channels, so no SD card required. I bought one to replace my Roku 4 a few weeks ago.