IFS Cycle 50r1 forecast production is currently running in parallel with the existing operational production. 
The details of this new model cycle (IFS Cy 50r1) are outlined on the Implementation of IFS Cycle 50r1 page. 

AIFS Single V2 and AIFS ENS V2 will be implemented on the same day as IFS Cycle 50r1. You can test the data in a similar way. The AIFS Single V2 and AIFS ENS V2 production is also running in parallel with the existing operational production. The details of these new models (AIFS Single V2 and AIFS ENS V2) are outlined on the Implementation of AIFS Single v2 and Implementation of AIFS ENS v2 pages. 

To support the rollout of Cycle 50r1 and AIFS Single V2 and AIFS ENS V2, we’re collecting the technical user and host configuration details required to deliver your test data during this Release Candidate Phase (RCP). Please provide the configuration for the environment where you would like your 50r1 test data delivered. 

All submitted information will be used solely for this RCP test phase and this form will be removed once the RCP concludes.

You can read about the testing procedure here: Testing for IFS Cycle 50r1