SSISDB - Certificates expired

I was doing an audit of certificates in our environments to find those that have either expired or are expiring in 30 days. I used the following query: SELECT * FROM sys.certificates WHERE expiry_date < DATEADD(DAY,30,GETDATE()); I noticed in SSISDB that there are a large number of expired certificates: What are these certificates used for, is it an issue that they have expired? I have not heard any complaints from our development team that SSIS isn't working as expected.