adding August 01 as deadline for link updates

_posts/2021/04/2021-04-27-announce-hifis-event-platform.md

@@ -49,7 +49,7 @@ If you are managing an event we recommend to check if everything still is as it
 ## What about the links I saved earlier?
 
 We created a redirection from the old to the new instance, so all links are still valid.
-However, this will not be indefinitely the case: **Please remember to update your bookmarks**, by replacing the old URL `hifis-events.hzdr.de` by the new `events.hifis.net`.
+However, this will only be the case until August 01, 2021, so **please remember to update your bookmarks**, by replacing the old URL `hifis-events.hzdr.de` by the new `events.hifis.net`.
 
 ## Who to call?