== Adding Captured Hold Phone Notification Number to Checkin Repsonse ==

Some third party systems can phone users when a SIP checkin captures
an item they have on hold. Normally, to do this a patron information
request is sent (message pair 63/64), but some systems will only look
for it in the reply to the Checkin pair, 09/10. Because this is not
a part of the SIP2 standard and exposes patron personal information
when used indescriminately, it must be enabled by including the key
`<phone_ext_on_msg10 enabled="true" />` in the "institution"
section of `oils_sip.xml`.

=== Upgrade Note ===

To use this feature, Evergreen administrators should upgrade to the
latest version of `SIPServer`.