diff -pruN 2.6.4-8.1/debian/changelog 2.6.4-8.2/debian/changelog
--- 2.6.4-8.1/debian/changelog	2023-05-20 21:06:26.000000000 +0000
+++ 2.6.4-8.2/debian/changelog	2023-05-20 21:06:27.000000000 +0000
@@ -1,3 +1,14 @@
+flex (2.6.4-8.2) unstable; urgency=medium
+
+  * Non-maintainer upload.
+  * Fix package-relationships with flex-old:
+    + Add flex Conflicts/Replaces flex-old
+    + Change versioned libfl2-dev Replaces/Breaks against flex-old (<=
+      2.5.4a-10) to unversioned Conflicts/Replaces flex-old.
+    Closes: #1034931
+
+ -- Andreas Metzler <ametzler@debian.org>  Thu, 18 May 2023 11:33:49 +0200
+
 flex (2.6.4-8.1) unstable; urgency=medium
 
   * Non-maintainer upload.
diff -pruN 2.6.4-8.1/debian/control 2.6.4-8.2/debian/control
--- 2.6.4-8.1/debian/control	2023-05-20 21:06:26.000000000 +0000
+++ 2.6.4-8.2/debian/control	2023-05-20 21:06:27.000000000 +0000
@@ -16,6 +16,8 @@ Package: flex
 Architecture: any
 Pre-Depends: debconf | debconf-2.0
 Depends: ${shlibs:Depends}, m4, ${misc:Depends}
+Conflicts: flex-old
+Replaces: flex-old
 Recommends: gcc | c-compiler, libfl-dev
 Suggests: bison, build-essential, flex-doc
 Multi-Arch: foreign
@@ -70,8 +72,9 @@ Section: libdevel
 Architecture: any
 Multi-Arch: same
 Depends: ${misc:Depends}, flex (= ${binary:Version}), libfl2 (= ${binary:Version})
-Replaces: flex (<< 2.5.39), flex-old (<= 2.5.4a-10)
-Breaks: flex (<< 2.5.39), flex-old (<= 2.5.4a-10)
+Replaces: flex (<< 2.5.39), flex-old
+Breaks: flex (<< 2.5.39)
+Conflicts: flex-old
 Description: static library for flex (a fast lexical analyzer generator)
  Flex is a tool for generating scanners: programs which recognized lexical
  patterns in text. It reads the given input files for a description of a