diff --git a/.gitmodules b/.gitmodules
index 2604287..037dc1c 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -55,6 +55,9 @@
 [submodule "magit-tbdiff"]
 	path = lib/magit-tbdiff
 	url = git@github.com:magit/magit-tbdiff.git
+[submodule "markdown-mode"]
+	path = lib/markdown-mode
+	url = git@github.com:jrblevin/markdown-mode.git
 [submodule "mode-line-debug"]
 	path = lib/mode-line-debug
 	url = git@github.com:tarsius/mode-line-debug.git
diff --git a/lib/markdown-mode b/lib/markdown-mode
new file mode 160000
index 0000000..cde5c5d
--- /dev/null
+++ b/lib/markdown-mode
@@ -0,0 +1 @@
+Subproject commit cde5c5d2bcce470c494b76e23cfe1364b6291c20
diff --git a/lib/no-littering b/lib/no-littering
index d556a4c..a4b42b1 160000
--- a/lib/no-littering
+++ b/lib/no-littering
@@ -1 +1 @@
-Subproject commit d556a4cd3bfd3827c3d395ff6cd1e6086658589d
+Subproject commit a4b42b185b65e78bc3bb6523e23aefb1213eb3b2
diff --git a/lib/undo-tree b/lib/undo-tree
index a2fff39..9afaffe 160000
--- a/lib/undo-tree
+++ b/lib/undo-tree
@@ -1 +1 @@
-Subproject commit a2fff3959730c69a050543af07fe477dd83092ac
+Subproject commit 9afaffee7b40367632dc3c9385284da2cfe4877e