diff --git a/master_changes.md b/master_changes.md
index f2a0cf8c0a7..03949cf57b0 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -64,6 +64,8 @@ New option/command/subcommand are prefixed with ◈.
   * Upgrade vendored cmdliner to 1.2.0 [#5797 @kit-ty-kate]
   * Add winsymlinks:native to the CYGWIN environment variable when installing a package on Windows [#5793 @kit-ty-kate - fix #5782]
   * Upgrade the vendored dune to 3.14.0 [#5869 @kit-ty-kate]
+  * Vendor mccs.1.1+17 [#5769 @kit-ty-kate]
+  * Require mccs >= 1.1+17 [#5769 @kit-ty-kate]
 
 ## Infrastructure
   *
@@ -81,6 +83,7 @@ New option/command/subcommand are prefixed with ◈.
 
 ## Solver
   *
+  * Fix debug logs showing up regardless of verbosity on macOS 12.7.1 / 13.6.3 / 14.2 and FreeBSD [#5769 @kit-ty-kate]
 
 ## Client
 
diff --git a/opam-solver.opam b/opam-solver.opam
index acb5318a869..5aeea4a16a7 100644
--- a/opam-solver.opam
+++ b/opam-solver.opam
@@ -28,7 +28,7 @@ build: [
 depends: [
   "ocaml" {>= "4.02.3"}
   "opam-format" {= version}
-  "mccs" {>= "1.1+9"}
+  "mccs" {>= "1.1+17"}
   ("dose3" {>= "6.1"} | "dose3" {>= "5"} & "ocaml" {= "4.02.3"})
   "cudf" {>= "0.7"}
   "dune" {>= "1.11.0"}
diff --git a/src_ext/Makefile.sources b/src_ext/Makefile.sources
index 4def6681f04..ebbf2b0e655 100644
--- a/src_ext/Makefile.sources
+++ b/src_ext/Makefile.sources
@@ -38,8 +38,8 @@ MD5_dose3 = bc99cbcea8fca29dca3ebbee54be45e1
 
 $(call PKG_SAME,dose3)
 
-URL_mccs = https://github.com/AltGr/ocaml-mccs/archive/1.1+13.tar.gz
-MD5_mccs = 13504d3b5dcbf0bdc6d95a62de20af4a
+URL_mccs = https://github.com/ocaml-opam/ocaml-mccs/archive/refs/tags/1.1+17.tar.gz
+MD5_mccs = 844d99bc531e0713238fe4b6b8511ed1
 
 $(call PKG_SAME,mccs)