diff --git a/bookshop/package.json b/bookshop/package.json
index 25a9f529..e7125251 100644
--- a/bookshop/package.json
+++ b/bookshop/package.json
@@ -4,7 +4,7 @@
   "description": "A simple self-contained bookshop service.",
   "dependencies": {
     "@capire/common": "*",
-    "@sap/cds": ">=4",
+    "@sap/cds": "^5.0.4",
     "express": "^4.17.1",
     "passport": "0.4.1"
   },
diff --git a/bookshop/srv/cat-service.js b/bookshop/srv/cat-service.js
index 4676dcd5..a27aa397 100644
--- a/bookshop/srv/cat-service.js
+++ b/bookshop/srv/cat-service.js
@@ -5,10 +5,10 @@ class CatalogService extends cds.ApplicationService { init(){
 
   // Reduce stock of ordered books if available stock suffices
   this.on ('submitOrder', async req => {
-    const {book,amount} = req.data, tx = cds.tx(req)
-    let {stock} = await tx.read('stock').from(Books,book)
+    const {book,amount} = req.data
+    let {stock} = await SELECT `stock` .from (Books,book)
     if (stock >= amount) {
-      await tx.update (Books,book).with ({ stock: stock -= amount })
+      await UPDATE (Books,book) .with (`stock -=`, amount)
       await this.emit ('OrderedBook', { book, amount, buyer:req.user.id })
       return { stock }
     }
@@ -16,10 +16,8 @@ class CatalogService extends cds.ApplicationService { init(){
   })
 
   // Add some discount for overstocked books
-  this.after ('READ','Books', each => {
-    if (each.stock > 111) {
-      each.title += ` -- 11% discount!`
-    }
+  this.after ('READ','ListOfBooks', each => {
+    if (each.stock > 111) each.title += ` -- 11% discount!`
   })
 
   return super.init()
diff --git a/test/messaging.test.js b/test/messaging.test.js
index 42d20d38..3e2176b1 100644
--- a/test/messaging.test.js
+++ b/test/messaging.test.js
@@ -20,11 +20,11 @@ describe('Messaging', ()=>{
 
     let N=0, received=[], M=0
     it ('should add messaging event handlers', ()=>{
-        srv.on('reviewed', (msg,next)=> { received.push(msg); return next() })
+        srv.on('reviewed', (msg)=> received.push(msg))
     })
 
     it ('should add more messaging event handlers', ()=>{
-        srv.on('reviewed', (_,next)=> { ++M; return next() })
+        srv.on('reviewed', ()=> ++M)
     })
 
     it ('should add review', async ()=>{