diff --git a/src/v1/routes/client.js b/src/v1/routes/client.js
index 5c91983..3a40e48 100644
--- a/src/v1/routes/client.js
+++ b/src/v1/routes/client.js
@@ -69,6 +69,13 @@ export function buildClientStep2(authCode, config) {
  *     security: []
  *     x-markdown: pos/client.md
  *     parameters:
+ *       - in: header
+ *         name: version
+ *         required: false
+ *         schema:
+ *           type: string
+ *         description: POS client software version (e.g. 2.0.0.5)
+ *         example: "2.0.0.5"
  *       - in: query
  *         name: authCode
  *         required: true
@@ -167,13 +174,14 @@ export async function handleClient(req, res) {
                 const token = terminal.token;
                 const strToken = String(token || crypto.randomBytes(16).toString('hex')).trim();
                 const pairedAt = serverTimestamp();
-                const clientversion = req.query.clientversion || req.query.version || req.query.clientVersion || null;
+                const rawVersion = req.headers.version || req.headers.clientversion || req.query.clientversion || req.query.version || req.query.clientVersion || null;
+                const clientversion = rawVersion ? String(rawVersion).trim() : null;
 
                 await db.pair(terminal.id, {
                     token: strToken,
                     clientserial: name,
                     pairedAt,
-                    clientversion: clientversion ? String(clientversion).trim() : null,
+                    clientversion,
                 });
 
                 if (terminal.companyId) {
diff --git a/src/v1/routes/init.js b/src/v1/routes/init.js
index 0d2e01f..d522cb8 100644
--- a/src/v1/routes/init.js
+++ b/src/v1/routes/init.js
@@ -1,4 +1,5 @@
 import * as db from '../../db/posterminal.js';
+import { emit } from '../../api/sse.js';
 
 /**
  * @openapi
@@ -19,6 +20,13 @@ import * as db from '../../db/posterminal.js';
  *           type: string
  *         description: POS device authToken obtained during pairing (`Bearer <token>` or `<token>`)
  *         example: "Bearer c30099b66ec1fcb9ccd05795423c94e8"
+ *       - in: header
+ *         name: version
+ *         required: false
+ *         schema:
+ *           type: string
+ *         description: POS client software version reported by the device
+ *         example: "2.0.0.5"
  *       - in: query
  *         name: lastChangedProduct
  *         required: false
@@ -121,6 +129,23 @@ import * as db from '../../db/posterminal.js';
 export async function handleInit(req, res) {
     const posterminalId = req.posterminal.id;
 
+    const rawVersion = req.headers.version || req.headers.clientversion;
+    const incomingVersion = rawVersion ? String(rawVersion).trim() : '';
+    const currentVersion = req.posterminal.clientversion ? String(req.posterminal.clientversion).trim() : '';
+
+    const updateVersionPromise = (incomingVersion && incomingVersion !== currentVersion)
+        ? db.setClientversion(posterminalId, incomingVersion)
+            .then(() => {
+                req.posterminal.clientversion = incomingVersion;
+                if (req.posterminal.companyId) {
+                    emit('posterminal', { companyId: req.posterminal.companyId });
+                }
+            })
+            .catch((err) => {
+                console.error(`Failed to update posterminal ${posterminalId} version:`, err);
+            })
+        : null;
+
     const productCursor = Number(req.query.lastChangedProduct) || 0;
     const categoryCursor = Number(req.query.lastChangedCategory) || 0;
     const customerCursor = Number(req.query.lastChangedCustomer) || 0;
@@ -145,6 +170,7 @@ export async function handleInit(req, res) {
             db.getCompositeProductCount({ posterminalId, cursor: compositeProductCursor }),
             db.getDeletedEntityCount({ posterminalId, cursor: deletedEntityCursor }),
             db.getMaxOrderIdCount({ posterminalId }),
+            updateVersionPromise,
         ]);
 
         return res.status(200).json({