For the no-tenant deployments the piler daemons have started to enforce the max. release feature.
Every piler build has a release date, eg. 20210501. You are entitled to use a specific build if your max. release value is greater then release date baked in the piler daemons.
Otherwise you may see similar errors in the mail logs:
May 1 13:06:37 cust1 piler/smtp: ERROR: You are not licensed to use release 20210501 (expired on 20210430) May 1 13:06:37 cust1 piler/smtp: ERROR: Visit https://mailpiler.com/software-maintenance for more info May 1 13:06:37 cust1 piler/smtp: ERROR: You are not licensed to use this release May 1 13:06:37 cust1 piler/smtp: piler-smtp has been terminated
Please write to sales AT mailpiler.com and order the annual software updates. It’s 25% of the current one-time price based on the user count. After the payment you’ll get an updated license allowing you to use the most recent piler build.
Until then you may downgrade to the previous software release you are using.