diff -Nru less-551/debian/changelog less-551/debian/changelog
--- less-551/debian/changelog	2019-09-15 02:28:16.000000000 +0000
+++ less-551/debian/changelog	2020-07-01 23:25:13.000000000 +0000
@@ -1,3 +1,12 @@
+less (551-1ubuntu0.1) focal; urgency=medium
+
+  * On upgrade from packages that shipped less in both /bin and /usr/bin,
+    call update-alternatives in preinst, such that after unpacking,
+    /usr/bin/pager remains operational. This should resolve dpkg failing
+    to invoke pager by dpkg. LP: #1874953
+
+ -- Brian Murray <brian@ubuntu.com>  Wed, 01 Jul 2020 16:25:13 -0700
+
 less (551-1) sid; urgency=low
 
   * many thanks to Anibal Monsalve Salazar for a decade worth of contributions
diff -Nru less-551/debian/control less-551/debian/control
--- less-551/debian/control	2019-09-13 05:23:24.000000000 +0000
+++ less-551/debian/control	2020-06-05 15:18:51.000000000 +0000
@@ -1,7 +1,8 @@
 Source: less
 Section: text
 Priority: important
-Maintainer: Milan Kupcevic <milan@debian.org>
+Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
+XSBC-Original-Maintainer: Milan Kupcevic <milan@debian.org>
 Build-Depends:
  debhelper (>= 12),
  libncurses-dev
diff -Nru less-551/debian/preinst less-551/debian/preinst
--- less-551/debian/preinst	1970-01-01 00:00:00.000000000 +0000
+++ less-551/debian/preinst	2020-06-05 15:18:51.000000000 +0000
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+set -e
+
+case "$1" in
+    upgrade)
+        if dpkg --compare-versions "$2" le "551-1"; then
+            update-alternatives --quiet --install /usr/bin/pager pager \
+              /usr/bin/less 77 --slave /usr/share/man/man1/pager.1.gz \
+              pager.1.gz /usr/share/man/man1/less.1.gz
+            update-alternatives --quiet --remove pager /bin/less            
+        fi
+        ;;
+esac
+
+#DEBHELPER#
+
+exit 0