All good things come to an end.
To assure that all certifications are up to date and relevant, the syllabi are regularly revised by their developers. Therefore, from time to time, there are expiration dates from outdated syllabus versions. In the nearest future the ISTQB Advanced Level Test Analyst 2012 & Technical Test Analyst 2012, the IREB CPRE Foundation Level 2.2 & the IBUQ CPUE Syllabi expire.
All expiration dates / sunset dates can be found here.