diff --git a/regex-capi/Cargo.toml b/regex-capi/Cargo.toml
index 78867f463..5ba88782f 100644
--- a/regex-capi/Cargo.toml
+++ b/regex-capi/Cargo.toml
@@ -11,7 +11,8 @@ description = """
 A C API for Rust's regular expression library.
 """
 workspace = ".."
-edition = "2018"
+edition = "2021"
+rust-version = "1.65"
 
 [lib]
 name = "rure"
diff --git a/regex-capi/src/error.rs b/regex-capi/src/error.rs
index 7b91fb9d3..c2af42084 100644
--- a/regex-capi/src/error.rs
+++ b/regex-capi/src/error.rs
@@ -60,7 +60,7 @@ ffi_fn! {
 ffi_fn! {
     fn rure_error_message(err: *mut Error) -> *const c_char {
         let err = unsafe { &mut *err };
-        let cmsg = match CString::new(format!("{}", err)) {
+        let cmsg = match CString::new(format!("{err}")) {
             Ok(msg) => msg,
             Err(err) => {
                 // I guess this can probably happen if the regex itself has a
diff --git a/regex-capi/src/macros.rs b/regex-capi/src/macros.rs
index 7807cf853..6de0b6827 100644
--- a/regex-capi/src/macros.rs
+++ b/regex-capi/src/macros.rs
@@ -20,8 +20,8 @@ macro_rules! ffi_fn {
                     };
                     let _ = writeln!(
                         &mut io::stderr(),
-                        "panic unwind caught, aborting: {:?}",
-                        msg);
+                        "panic unwind caught, aborting: {msg:?}"
+                    );
                     unsafe { abort() }
                 }
             }
diff --git a/regex-capi/src/rure.rs b/regex-capi/src/rure.rs
index 9e17668e2..8fe697dbe 100644
--- a/regex-capi/src/rure.rs
+++ b/regex-capi/src/rure.rs
@@ -82,7 +82,7 @@ ffi_fn! {
         let re = rure_compile(
             pat, len, RURE_DEFAULT_FLAGS, ptr::null(), &mut err);
         if err.is_err() {
-            let _ = writeln!(&mut io::stderr(), "{}", err);
+            let _ = writeln!(&mut io::stderr(), "{err}");
             let _ = writeln!(
                 &mut io::stderr(), "aborting from rure_compile_must");
             unsafe { abort() }
@@ -579,7 +579,7 @@ ffi_fn! {
         let mut err = Error::new(ErrorKind::None);
         let esc = rure_escape(pat, len, &mut err);
         if err.is_err() {
-            let _ = writeln!(&mut io::stderr(), "{}", err);
+            let _ = writeln!(&mut io::stderr(), "{err}");
             let _ = writeln!(
                 &mut io::stderr(), "aborting from rure_escape_must");
             unsafe { abort() }