Managed Migration IS to UC

My husband used to claim IRESA. He was in the support group but was subjected to reassessment every year. To avoid the stress of these reassessments, 8 years ago my husband stopped claiming ESA and I claimed IS instead. Jobcentre agreed to waive the requirement for my husband to attend Jobcentre appointments. This year we will have to move over to UC under managed migration. Will my husband have to undergo a WCA? will we get transitional protection?. Thank you.

Thanks Gordon. Further to this if a Fit Note were to be submitted at the point of applying for UC, would transitional protection continue to be applied up until the outcome of the WCA assessment?..
Do couples receive managed migration notices at the same time?..