diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf68b8f..9b74af8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.3.5 — 2026-09-01
+
+- Interpret the ChatGPT desktop version date segment (`YY.MDD`) for the
+  launch-button tooltip, with the local package/update date as a fallback for
+  versions that do not match the observed format.
+
 ## 0.3.4 — 2026-09-01
 
 - Derive the ChatGPT launch-button date dynamically from the installed
diff --git a/README.md b/README.md
index 1262c76..e9ae01e 100644
--- a/README.md
+++ b/README.md
@@ -66,9 +66,10 @@
   native expandable section, which opens automatically after recent activity.
 - Launches an installed ChatGPT desktop app or Codex CLI directly, with native
   installation guidance when either is missing. Web shortcuts cover ChatGPT,
-  Codex Cloud and ChatGPT Analytics. The ChatGPT launch tooltip derives its
-  displayed date from the installed executable's local package/update timestamp;
-  this is not an upstream publication-date guarantee.
+  Codex Cloud and ChatGPT Analytics. The ChatGPT launch tooltip interprets the
+  observed date segment in the desktop version (`YY.MDD`) and falls back to the
+  installed executable's local package/update timestamp when that format is
+  unavailable; neither is an upstream publication-date guarantee.
 - Shows `5h` automatically only when an active API limit exposes that window;
   an accompanying `7d` panel block can be hidden in settings while unnamed
   internal buckets stay hidden.
@@ -94,7 +95,7 @@ cd cinnamon-chatgpt-usage
 Then open **System Settings → Applets** and add **ChatGPT Usage** to a panel.
 Requirements: Cinnamon 5.8+, Python 3 and a current
 [Codex CLI](https://learn.chatgpt.com/docs/codex/cli#getting-started) signed in
-with ChatGPT. Version 0.3.4 is tested on Cinnamon 6.6.9 with Codex CLI 0.152.0.
+with ChatGPT. Version 0.3.5 is tested on Cinnamon 6.6.9 with Codex CLI 0.152.0.
 
 Run `./install.sh` again after updates. `./uninstall.sh` removes the applet while
 retaining its settings.
diff --git a/applet.js b/applet.js
index d8ab40e..54d051b 100644
--- a/applet.js
+++ b/applet.js
@@ -1046,6 +1046,7 @@ class ChatGptUsageApplet extends Applet.Applet {
         const codexPath = this._resolveCodexPath();
         const codexCommand = this._codexTerminalCommand(codexPath);
         const chatGptVersion = this._chatGptAppVersion(chatGptApp);
+        const chatGptVersionDate = UsageFormat.formatChatGptVersionDate(chatGptVersion);
         const chatGptInstallDate = this._chatGptAppInstallDate(chatGptApp);
         const codexVersion = this._commandVersion(codexPath);
         const item = new PopupMenu.PopupBaseMenuItem({
@@ -1110,7 +1111,7 @@ class ChatGptUsageApplet extends Applet.Applet {
                 Boolean(chatGptApp),
                 chatGptVersion,
                 "chatgpt",
-                chatGptInstallDate
+                chatGptVersionDate || chatGptInstallDate
             )
         );
         this._codexButton = this._createLaunchButton(
diff --git a/metadata.json b/metadata.json
index 82f41c6..78f833b 100644
--- a/metadata.json
+++ b/metadata.json
@@ -4,7 +4,7 @@
   "description": "A tiny Cinnamon companion that keeps ChatGPT Work and Codex usage beautifully in view.",
   "comments": "Made with love by Claudiu & Codex. 🩷\n\nhttps://github.com/oss-singularity/cinnamon-chatgpt-usage",
   "contributors": "OSS Singularity — open-source home of the project,Claudiu Schuster — creator and maintainer,OpenAI Codex — design and engineering collaborator",
-  "version": "0.3.4",
+  "version": "0.3.5",
   "author": "OSS Singularity",
   "max-instances": 1,
   "cinnamon-version": ["5.8", "6.0", "6.2", "6.4", "6.6"],
diff --git a/tests/test-usage-format.js b/tests/test-usage-format.js
index 688b7b7..e740433 100644
--- a/tests/test-usage-format.js
+++ b/tests/test-usage-format.js
@@ -511,6 +511,31 @@ assertEqual(
     null,
     "Invalid application package timestamp has no date"
 );
+assertEqual(
+    UsageFormat.formatChatGptVersionDate("26.831.20005"),
+    "31.08.2026",
+    "ChatGPT version date decodes August 31, 2026"
+);
+assertEqual(
+    UsageFormat.formatChatGptVersionDate("26.825.51511"),
+    "25.08.2026",
+    "ChatGPT version date decodes August 25, 2026"
+);
+assertEqual(
+    UsageFormat.formatChatGptVersionDate("26.406.40811"),
+    "06.04.2026",
+    "ChatGPT version date decodes April 6, 2026"
+);
+assertEqual(
+    UsageFormat.formatChatGptVersionDate("26.1001.20005"),
+    "01.10.2026",
+    "ChatGPT version date supports two-digit months"
+);
+assertEqual(
+    UsageFormat.formatChatGptVersionDate("new-version"),
+    null,
+    "Unknown ChatGPT version has no decoded build date"
+);
 assertEqual(
     UsageFormat.formatAppTooltip(true, "codex-cli 0.152.0", "", "01.09.2026"),
     "codex-cli 0.152.0 — 01.09.2026",
diff --git a/usage-format.js b/usage-format.js
index 4eebc4b..1570e0d 100644
--- a/usage-format.js
+++ b/usage-format.js
@@ -527,6 +527,27 @@ function formatLocalDate(epochSeconds) {
     return dateTime.format("%d.%m.%Y");
 }
 
+function formatChatGptVersionDate(version) {
+    const match = String(version || "").trim().match(/^(\d{2})\.(\d{3,4})\.\d{5}$/);
+    if (!match) return null;
+
+    const year = 2000 + Number(match[1]);
+    const dateCode = match[2];
+    const month = Number(dateCode.slice(0, -2));
+    const day = Number(dateCode.slice(-2));
+    const date = new Date(Date.UTC(year, month - 1, day));
+    if (
+        month < 1 || month > 12 || day < 1 ||
+        date.getUTCFullYear() !== year ||
+        date.getUTCMonth() !== month - 1 ||
+        date.getUTCDate() !== day
+    ) {
+        return null;
+    }
+
+    return `${String(day).padStart(2, "0")}.${String(month).padStart(2, "0")}.${year}`;
+}
+
 function formatRelativeTime(epochSeconds, nowSeconds = null) {
     const updatedSeconds = Number(epochSeconds);
     const currentSeconds = nowSeconds === null
@@ -581,6 +602,7 @@ module.exports = {
     formatAccessibleTooltip,
     formatTimestamp,
     formatLocalDate,
+    formatChatGptVersionDate,
     formatRelativeTime,
     formatAppTooltip
 };