diff --git a/.gitignore b/.gitignore
index 4c250d2..8a5f043 100644
--- a/.gitignore
+++ b/.gitignore
@@ -91,3 +91,4 @@ mercurial-1.6.2.tar.gz
 /mercurial-6.3.1.tar.gz
 /mercurial-6.3.2.tar.gz
 /mercurial-6.3.3.tar.gz
+/mercurial-6.4.tar.gz
diff --git a/mercurial-rust-metadata.patch b/mercurial-rust-metadata.patch
index e810849..2133ed7 100644
--- a/mercurial-rust-metadata.patch
+++ b/mercurial-rust-metadata.patch
@@ -1,29 +1,15 @@
 Patch cargo metadata for Fedora build
 
-Update zstd to 0.12.0 (upstream is stuck on 0.5 because MSRV)
- - adapt for breaking changes in zstd 0.10.0
+Keep using old bytes-cast for now - https://www.mercurial-scm.org/repo/hg/rev/da02e88b4850 indicates that should be ok.
 
-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
-@@ -34,7 +34,7 @@
- micro-timer = "0.4.0"
- log = "0.4.8"
- memmap2 = { version = "0.5.3", features = ["stable_deref_trait"] }
--zstd = "0.5.3"
-+zstd = "0.12"
- format-bytes = "0.3.0"
- # once_cell 1.15 uses edition 2021, while the heptapod CI
- # uses an old version of Cargo that doesn't support it.
-diff --git a/rust/hg-core/src/revlog/revlog.rs b/rust/hg-core/src/revlog/revlog.rs
---- a/rust/hg-core/src/revlog/revlog.rs
-+++ b/rust/hg-core/src/revlog/revlog.rs
-@@ -513,7 +513,7 @@ impl<'a> RevlogEntry<'a> {
-         } else {
-             let cap = self.uncompressed_len.max(0) as usize;
-             let mut buf = vec![0; cap];
--            let len = zstd::block::decompress_to_buffer(self.bytes, &mut buf)
-+            let len = zstd::bulk::decompress_to_buffer(self.bytes, &mut buf)
-                 .map_err(|e| corrupted(e.to_string()))?;
-             if len != self.uncompressed_len as usize {
-                 Err(corrupted("uncompressed length does not match"))
+@@ -10,7 +10,7 @@ name = "hg"
+
+ [dependencies]
+ bitflags = "1.3.2"
+-bytes-cast = "0.3.0"
++bytes-cast = "0.2.0"
+ byteorder = "1.4.3"
+ derive_more = "0.99.17"
+ hashbrown = { version = "0.13.1", features = ["rayon"] }
diff --git a/mercurial.spec b/mercurial.spec
index 23cc65f..64c3a5a 100644
--- a/mercurial.spec
+++ b/mercurial.spec
@@ -9,7 +9,7 @@
 
 Summary: A fast, lightweight Source Control Management system
 Name: mercurial
-Version: 6.3.3
+Version: 6.4
 Release: 1%{?dist}
 
 # Release: 1.rc1%%{?dist}
@@ -273,6 +273,9 @@ rm -rf %{buildroot}%{python3_sitearch}/mercurial/locale
 
 
 %changelog
+* Fri Mar 24 2023 Mads Kiilerich <mads@kiilerich.com> - 6.4-1
+- mercurial 6.4
+
 * Thu Mar 02 2023 Mads Kiilerich <mads@kiilerich.com> - 6.3.3-1
 - mercurial 6.3.3
 
diff --git a/sources b/sources
index 788ee8c..1cbc87a 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-SHA512 (mercurial-6.3.3.tar.gz) = 2c09ec01857552e92dee2ff946444f6ccd86a7249561d2181f339aa66316e9ce0f19399895782d0b63c1b5fdb6d341f866d166616ae51a78bac7e1bb4128a0fd
+SHA512 (mercurial-6.4.tar.gz) = a7810eddd0fd2a331215a5f7e9c81df4d860cf695aec3c5e3984821827b5427b5a01b68c07b9711e86db2f9b0ef5b5d3d6251a7dc76f99375c457920ce36c96f