diff --git a/build.rs b/build.rs
index 0a3d19be1..6c69b391a 100644
--- a/build.rs
+++ b/build.rs
@@ -6,10 +6,13 @@ use std::path::Path;
 fn main() {
     let version = std::env::var("CARGO_PKG_VERSION").expect("Cargo package version");
     let parts: Vec<&str> = version.split('.').collect();
-    let app_version = if parts.len() == 3 && parts[0].len() == 4
-        && parts[0].starts_with("20") && parts[2] == "0"
-    {
-        format!("{}.{:02}", parts[0], parts[1].parse::<u32>().expect("week number"))
+    let app_version = if parts.len() == 3 && parts[0].len() == 4 && parts[0].starts_with("20") {
+        let week = parts[1].parse::<u32>().expect("week number");
+        if parts[2] == "0" {
+            format!("{}.{week:02}", parts[0])
+        } else {
+            format!("{}.{week:02}.{}", parts[0], parts[2])
+        }
     } else {
         version.clone()
     };
diff --git a/scripts/release.py b/scripts/release.py
index 96b7ae1c9..28bafe5c4 100644
--- a/scripts/release.py
+++ b/scripts/release.py
@@ -21,12 +21,14 @@ def gh(*args):
 
 def versions(tag):
     version = tag.removeprefix("v")
-    weekly = re.fullmatch(r"(20\d{2})\.(\d{2})", version)
+    # `2026.40` is the weekly release; `2026.40.1` a fix release on top of it.
+    weekly = re.fullmatch(r"(20\d{2})\.(\d{2})(?:\.([1-9]\d*))?", version)
     if weekly:
-        year, week = map(int, weekly.groups())
+        year, week = int(weekly[1]), int(weekly[2])
+        patch = int(weekly[3] or 0)
         date.fromisocalendar(year, week, 1)
-        cargo = f"{year}.{week}.0"
-        msi = f"{year - 2000}.{week}.0"
+        cargo = f"{year}.{week}.{patch}"
+        msi = f"{year - 2000}.{week}.{patch}"
     elif re.fullmatch(r"(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)", version):
         cargo = msi = version
         major, minor, patch = map(int, version.split("."))
@@ -43,8 +45,9 @@ def cargo_version():
 
 def display_version(cargo):
     year, week, patch = cargo.split(".")
-    if len(year) == 4 and year.startswith("20") and patch == "0":
-        return versions(f"{year}.{int(week):02}")["version"]
+    if len(year) == 4 and year.startswith("20"):
+        weekly = f"{year}.{int(week):02}"
+        return versions(weekly if patch == "0" else f"{weekly}.{patch}")["version"]
     return cargo
 
 
diff --git a/scripts/test_release.py b/scripts/test_release.py
index 753c09595..d5c6b9257 100644
--- a/scripts/test_release.py
+++ b/scripts/test_release.py
@@ -50,7 +50,7 @@ class ReleaseTests(unittest.TestCase):
         with tempfile.TemporaryDirectory() as temp:
             binary = str(Path(temp) / "build-script")
             subprocess.run(["rustc", str(Path(__file__).resolve().parents[1] / "build.rs"), "-o", binary], check=True)
-            for cargo in ("0.9.8", "2026.9.0", "2026.35.0", "2026.53.0", "2027.1.0"):
+            for cargo in ("0.9.8", "2026.9.0", "2026.35.0", "2026.53.0", "2027.1.0", "2026.40.1", "2026.5.2"):
                 result = subprocess.check_output([binary], text=True, env={**os.environ, "CARGO_PKG_VERSION": cargo})
                 self.assertIn(f"cargo:rustc-env=OCS_APP_VERSION={release.display_version(cargo)}\n", result)
 
@@ -61,6 +61,10 @@ class ReleaseTests(unittest.TestCase):
         self.assertEqual(release.versions("2026.09")["cargo"], "2026.9.0")
         self.assertEqual(release.display_version("2026.9.0"), "2026.09")
         self.assertEqual(release.display_version("0.9.8"), "0.9.8")
+        self.assertEqual(release.versions("v2026.40.1"), {
+            "version": "2026.40.1", "cargo": "2026.40.1", "msi": "26.40.1", "tag": "v2026.40.1",
+        })
+        self.assertEqual(release.display_version("2026.5.2"), "2026.05.2")
         self.assertEqual(datetime(2027, 1, 3, tzinfo=timezone.utc).strftime("v%G.%V"), "v2026.53")
         for value in ("2026.00", "2026.54", "2027.53", "2026.9", "2026.35.0", "bad", "0.09.8"):
             with self.assertRaises(ValueError, msg=value):
diff --git a/src/io/update_check.rs b/src/io/update_check.rs
index cc24c402a..6c126bc08 100644
--- a/src/io/update_check.rs
+++ b/src/io/update_check.rs
@@ -137,10 +137,11 @@ fn parse_iso8601_utc(s: &str) -> Option<u64> {
 fn is_newer(latest: &str, installed: &str) -> bool {
     let parse = |version: &str| {
         let version = version.trim_start_matches('v');
-        if let Some((year, week)) = version.split_once('.') {
-            if year.len() == 4 && year.starts_with("20") && !week.contains('.') {
-                return Some(semver::Version::new(year.parse().ok()?, week.parse().ok()?, 0));
-            }
+        // `2026.40` and its fix release `2026.40.1`; the week may be zero-padded.
+        let parts: Vec<&str> = version.split('.').collect();
+        if (2..=3).contains(&parts.len()) && parts[0].len() == 4 && parts[0].starts_with("20") {
+            let patch = parts.get(2).map_or(Some(0), |patch| patch.parse().ok())?;
+            return Some(semver::Version::new(parts[0].parse().ok()?, parts[1].parse().ok()?, patch));
         }
         semver::Version::parse(version).ok()
     };
@@ -157,6 +158,9 @@ mod tests {
         assert!(is_newer("2026.10", "2026.09"));
         assert!(is_newer("2027.01", "2026.53"));
         assert!(!is_newer("2026.35", "2026.35"));
+        assert!(is_newer("2026.40.1", "2026.40"));
+        assert!(is_newer("2026.05.2", "2026.05.1"));
+        assert!(is_newer("2026.41", "2026.40.1"));
         assert!(!is_newer("0.9.8", "2026.35"));
         assert!(!is_newer("invalid", "2026.35"));
     }