Text to go in the release notes:
This fixes SIP connections so that when system preference and configuration changes are made (for example: enabling or disabling logging of issues and returns) they are picked up automatically with the next message, rather than requiring the SIP connection to be closed and reopened.
SIP connections typically tend to be long lived - weeks if not months. Basically the connection per SIP machine is initiated once when the SIP machine boots and then never closed until maintenance is required. Therefore we need to reset Koha's caches on every SIP request to get the latest system preference and configuration changes from the memcached cache that is shared between all the Koha programs (staff interface, OPAC, SIP, cronjobs, etc).