diff --git a/devel/devel20201128b-B4-changelog.txt b/devel/devel20201128b-B4-changelog.txt
new file mode 100644
index 0000000..036e991
--- /dev/null
+++ b/devel/devel20201128b-B4-changelog.txt
@@ -0,0 +1 @@
+updated dfm serial numbers
diff --git a/devel/devel20201128b-B4-full.bin b/devel/devel20201128b-B4-full.bin
new file mode 100644
index 0000000..8326ee7
Binary files /dev/null and b/devel/devel20201128b-B4-full.bin differ
diff --git a/devel/update.ino.bin b/devel/update.ino.bin
index 6ab4a36..710278c 100644
Binary files a/devel/update.ino.bin and b/devel/update.ino.bin differ
diff --git a/download.html b/download.html
index 322950e..ab4334d 100644
--- a/download.html
+++ b/download.html
@@ -107,7 +107,11 @@
 <br>test decode serial of dfm17 etc.
 </li>
 
-<li><a href="devel/update.ino.bin">update.ino.bin</a> (Nov 28 00:45:53 2020)
+<li><a href="devel/devel20201128b-B4-full.bin">devel20201128b-B4-full.bin</a> (Nov 28 18:55:39 2020)
+<br>updated dfm serial numbers
+</li>
+
+<li><a href="devel/update.ino.bin">update.ino.bin</a> (Nov 28 18:55:39 2020)
 </li>
 
 </ul>