dmeventd Changes Not Available

[Matthew Rubenstein]

	Hello. In my Ubuntu 18.04.2 LTS host the system-update
application has been offering for several weeks to upgrade 4 dmeventd
packages: dmeventd , libdevmapper-event1.02.1 , libdevmapper1.02.1 ,
dmsetup but the Technical description / Changes GUI says "The list of
changes is not available yet." Further, the URL offered in that GUI as
an alternate source of changes info leads to an invalid page:

http://launchpad.net/ubuntu/+source/lvm2/2%3A1.02.145-4.1ubuntu3.18.04.1/+changelog
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Lost something?
This page does not exist, or you may not have permission to see it.
[...]
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The same page content is produced if I url-decode the "%3A" to ":":

https://launchpad.net/ubuntu/+source/lvm2/2:1.02.145-4.1ubuntu3.18.04.1/+changelog
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Lost something?
This page does not exist, or you may not have permission to see it.

If you have been to this page before, it is possible it has been
removed.
[...]
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I do not trust this upgrade under these circumstances. Why is this
happening? How can we fix it? When can I safely upgrade these packages?
Thank you for your insights.