diff --git a/manifest b/manifest
index a879453a2b..54e45bc28b 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improved\scomment\son\sthe\sprpagateConstants()\sroutine.\s\sNo\schanges\sto\sexecutable\ncode.
-D 2021-05-27T14:09:01.854
+C Add\sthe\smerge-test.tcl\sscript\sto\sease\sverification\sof\sLTS\sbranches.
+D 2021-05-27T16:31:04.311
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -1842,6 +1842,7 @@ F tool/libvers.c caafc3b689638a1d88d44bc5f526c2278760d9b9
 F tool/loadfts.c c3c64e4d5e90e8ba41159232c2189dba4be7b862
 F tool/logest.c 11346aa019e2e77a00902aa7d0cabd27bd2e8cca
 F tool/max-limits.c cbb635fbb37ae4d05f240bfb5b5270bb63c54439
+F tool/merge-test.tcl de76b62f2de2a92d4c1ca4f976bce0aea6899e0229e250479b229b2a1914b176
 F tool/mkautoconfamal.sh f62353eb6c06ab264da027fd4507d09914433dbdcab9cb011cdc18016f1ab3b8
 F tool/mkccode.tcl 86463e68ce9c15d3041610fedd285ce32a5cf7a58fc88b3202b8b76837650dbe x
 F tool/mkctimec.tcl 06b0d503ee0e6c2d4abe83563b43d4925a12e31ec9fb3249ce39661f53fbd1ce
@@ -1917,7 +1918,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 4eb80b0cc61526c1ff7478b1b855b29fa4326daee61facd1d85e4297bb32ac9d
-R 816e0d4f9adc95e1495d0ff38bde7776
+P d61a875df48d8baab3ada0174c8e0312a9268bbd11bf104b4385eff9e2744266
+R 5e30c1492c2c1677fa63079c20b0d339
 U drh
-Z 0be2b6d4391de9cac15cfbee3096d192
+Z bcd233e14e52403e9c9befb82a37b462
diff --git a/manifest.uuid b/manifest.uuid
index eca5c5ff31..13fd3320c2 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d61a875df48d8baab3ada0174c8e0312a9268bbd11bf104b4385eff9e2744266
\ No newline at end of file
+f958ffbc61c693b71538cc3aa5f95ce0f0b5d4906efbb0c075f543e19883a669
\ No newline at end of file
diff --git a/tool/merge-test.tcl b/tool/merge-test.tcl
new file mode 100644
index 0000000000..2010d67657
--- /dev/null
+++ b/tool/merge-test.tcl
@@ -0,0 +1,99 @@
+#!/usr/bin/tcl
+#
+# Run this script to test to see that the latest trunk changes can be
+# merged into LTS branches without breaking anything.
+#
+# To Use:
+#
+#   *  Copy this script into a directory above the sqlite checkout
+#   *  Run "fossil update trunk" and "fossil revert"
+#   *  Run "tclsh ../merge-test.tcl"  (in other words run this script)
+#
+# Operation:
+#
+# This script changes to each LTS branch to be tested, merges the latest
+# trunk changes into the branch (without committing them) and then
+# runs "make test".  Any errors are stored in local files.
+#
+# Limitations:
+#
+# Some LTS branches are not synced directly from trunk but rather from
+# other LTS branches.  These other branches cannot be tested because
+# there is no good way to generate the intermediate merges.
+#
+###############################################################################
+
+# Run a shell command contained in arguments.  Put the return code in
+# global variable ::res and the output string in global variable ::result
+#
+proc safeexec {args} {
+  global res result
+  set res [catch "exec $args" result]
+}
+
+# Run the shell command contained in arguments.  Print an error and exit
+# if anything goes wrong.
+#
+proc mustbeok {args} {
+  global res result
+  set res [catch "exec $args" result]
+  if {$res} {
+    puts "FAILED: $args"
+    puts $result
+    exit 1
+  }
+}
+
+# Write $content into a file named $filename.  The file is overwritten if it
+# already exist.  The file is create if it does not already exist.
+#
+proc writefile {filename content} {
+  set fd [open $filename wb]
+  puts $fd $content
+  close $fd
+}
+
+# Run the merge-test
+#
+foreach {branch configopts} {
+  begin-concurrent         {--enable-json1}
+  begin-concurrent-pnu     {--enable-json1}
+  wal2                     {--enable-all}
+  reuse-schema             {--enable-all}
+} {
+  puts $branch
+  set errorfile ${branch}-error.txt
+  mustbeok fossil revert
+  mustbeok fossil up $branch
+  safeexec fossil merge trunk
+  if {$res} {
+    puts "   merge failed - see $errorfile"
+    writefile $errorfile $result
+  } else {
+    puts "   merge ok"
+    safeexec  ./configure --enable-debug {*}$configopts
+    if {$res} {
+      puts "   configure failed - see $errorfile"
+      writefile $errorfile $result
+    } else {
+      puts "   configure ok"
+      safeexec make fuzzcheck sqlite3 testfixture
+      if {$res} {
+        puts "   build failed - see $errorfile"
+        writefile $errorfile $result
+      } else {
+        puts "   build ok"
+        safeexec make test
+        if {$res} {
+          puts "   test failed - see $errorfile"
+          writefile $errorfile $result
+        } else {
+          puts "   test ok"
+        }
+      }
+    }
+  }
+}
+mustbeok fossil revert
+mustbeok fossil up trunk
+puts "reset back to trunk"