diff --git a/.gitignore b/.gitignore
index af0d7cc..3679dec 100644
--- a/.gitignore
+++ b/.gitignore
@@ -100,3 +100,4 @@ mercurial-1.6.2.tar.gz
 /mercurial-6.5.tar.gz
 /mercurial-6.5.1.tar.gz
 /mercurial-6.5.3.tar.gz
+/mercurial-6.6.tar.gz
diff --git a/mercurial-rust-metadata.patch b/mercurial-rust-metadata.patch
new file mode 100644
index 0000000..ada3dfd
--- /dev/null
+++ b/mercurial-rust-metadata.patch
@@ -0,0 +1,14 @@
+Patch cargo metadata for Fedora build
+
+diff --git a/rust/hg-core/Cargo.toml b/rust/hg-core/Cargo.toml
+--- a/rust/hg-core/Cargo.toml
++++ b/rust/hg-core/Cargo.toml
+@@ -31,7 +31,7 @@ sha-1 = "0.10.0"
+ twox-hash = "1.6.3"
+ same-file = "1.0.6"
+ tempfile = "3.3.0"
+-toml = "0.6"
++toml = "0.8"
+ thread_local = "1.1.4"
+ crossbeam-channel = "0.5.6"
+ log = "0.4.17"
diff --git a/mercurial.spec b/mercurial.spec
index 8f9bd7d..2c04d7e 100644
--- a/mercurial.spec
+++ b/mercurial.spec
@@ -9,8 +9,8 @@
 
 Summary: A fast, lightweight Source Control Management system
 Name: mercurial
-Version: 6.5.3
-Release: 2%{?dist}
+Version: 6.6
+Release: 1%{?dist}
 
 # Release: 1.rc1%%{?dist}
 
@@ -21,6 +21,8 @@ License: GPLv2+
 URL: https://mercurial-scm.org/
 Source0: https://www.mercurial-scm.org/release/%{name}-%{upstreamversion}.tar.gz
 Source1: mercurial-site-start.el
+# Patch cargo metadata for dependency versions available in Fedora
+Patch0:  mercurial-rust-metadata.patch
 BuildRequires: make
 BuildRequires: emacs-el
 BuildRequires: emacs-nox
@@ -258,6 +260,9 @@ rm -rf %{buildroot}%{python3_sitearch}/mercurial/locale
 
 
 %changelog
+* Tue Nov 21 2023 Mads Kiilerich <mads@kiilerich.com> - 6.6-1
+- mercurial 6.6 and patch to use cargo toml 0.8
+
 * Thu Nov 09 2023 Mads Kiilerich <mads@kiilerich.com> - 6.5.3-2
 - Better support for custom _prefix
 
diff --git a/sources b/sources
index 43b3ab8..2c28194 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-SHA512 (mercurial-6.5.3.tar.gz) = af90ec414fbf9da518ce0de5b855b5dd6e4141f838ab0da54a40f31aa00245d21f14f1352fe537744fb6ae5a3e4f2723076f4773fafac649b8483fefd002b510
+SHA512 (mercurial-6.6.tar.gz) = 3451a89156b9ca697658a94610264d525e7e509e6155cdb7d8e5ad09582f8831a11c6b6430bbb4abbe863e6d4fca3708e4a0d88afc7099f35778959321b8164a