Those with early Roku players will need to upgrade to carry on using the Netflix app - Netflix has said that support for older players will end on 1 December.
The players affected appear to be some players like the Roku HD and HD-XR (no, we don't have a precise list of devices).
This mostly affects those in the US, where Roku has been popular over a long period of time. Newer players are unaffected by the change so if you've something like a Roku TV, Roku 2, Premiere, Express or Streaming Stick you won't have a problem.
Roku also makes boxes for Now TV in the UK and, again, these players are not affected.
Cord Cutters News says that if you can't auto-play the next episode in a season your player will be among those that will lose support.
According to the information from Netflix, those affected will see an on-screen message. Cord Cutters News suggests yyou will be alerted as follows: "Due to technical limitations, Netflix will no longer be available on this device after December 1st, 2019. Please visit netflix.com/compatibledevices for a list of available devices".
Netflix should be on your home screen, but if not, set up Netflix on your Roku, go to Streaming Channels, then Movies & TV. Select Netflix, then Add Channel. Select Netflix.