diff --git a/packages/app/package.json b/packages/app/package.json
index 1cc57c9..e3851d1 100644
--- a/packages/app/package.json
+++ b/packages/app/package.json
@@ -47,7 +47,7 @@
     "@modular-api/quasar-components": "^0.3.0",
     "@quasar/extras": "1.16.12",
     "@quasar/quasar-ui-qcalendar": "4.0.0-beta.16",
-    "@simsustech/quasar-components": "^0.10.4",
+    "@simsustech/quasar-components": "^0.10.5",
     "@slimfact/api": "^0.1.0",
     "@trpc/client": "^10.45.2",
     "@trpc/server": "^10.45.2",
diff --git a/packages/app/src/components/company/CompanyForm.vue b/packages/app/src/components/company/CompanyForm.vue
index 63a876b..39fd7f7 100644
--- a/packages/app/src/components/company/CompanyForm.vue
+++ b/packages/app/src/components/company/CompanyForm.vue
@@ -127,13 +127,22 @@
         v-bind="input"
         v-model="modelValue.prefix"
         :label="lang.company.fields.prefix"
+        :readonly="prefixLocked"
         class="col-md-3 col-12"
         required
         bottom-slots
         lazy-rules
         name="prefix"
         :hint="lang.company.helpers.prefix"
-      />
+      >
+        <template #append>
+          <q-icon
+            class="clickable"
+            :name="prefixLocked ? 'lock_open' : 'lock'"
+            @click="prefixLocked = !prefixLocked"
+          />
+        </template>
+      </form-input>
       <form-input
         v-bind="input"
         v-model="modelValue.email"
@@ -256,6 +265,7 @@ const formRef = ref<QForm>()
 
 const setValue = (newValue: Company) => {
   modelValue.value = extend({}, initialValue, newValue)
+  if (newValue.prefix) prefixLocked.value = true
 }
 
 const submit: InstanceType<typeof ResponsiveDialog>['$props']['onSubmit'] = ({
@@ -272,6 +282,8 @@ const submit: InstanceType<typeof ResponsiveDialog>['$props']['onSubmit'] = ({
   done(false)
 }
 
+const prefixLocked = ref(false)
+
 const functions = ref({
   submit,
   setValue
diff --git a/packages/app/src/lang/en-US.ts b/packages/app/src/lang/en-US.ts
index 1d59c16..2018df2 100644
--- a/packages/app/src/lang/en-US.ts
+++ b/packages/app/src/lang/en-US.ts
@@ -75,7 +75,7 @@ const lang: Language = {
     },
     helpers: {
       emailBcc: 'All invoices will be sent as BCC to this address.',
-      prefix: 'The company prefix used in the invoice number prefix.'
+      prefix: 'The company prefix used in e.g. the invoice number prefix.'
     }
   },
   client: {
diff --git a/packages/app/src/lang/nl.ts b/packages/app/src/lang/nl.ts
index 83051c5..21d3383 100644
--- a/packages/app/src/lang/nl.ts
+++ b/packages/app/src/lang/nl.ts
@@ -76,7 +76,7 @@ const lang: Language = {
     helpers: {
       emailBcc: 'Alle facturen worden BCC verstuurd naar dit adres.',
       prefix:
-        'Het bedrijfsvoorvoegsel gebruikt in het nummervoorvoegsel van een factuur.'
+        'Het bedrijfsvoorvoegsel gebruikt in o.a. het nummervoorvoegsel van een factuur. '
     }
   },
   client: {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index c03a721..523df9d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -216,8 +216,8 @@ importers:
         specifier: 4.0.0-beta.16
         version: 4.0.0-beta.16
       '@simsustech/quasar-components':
-        specifier: ^0.10.4
-        version: 0.10.4(quasar@2.17.0)
+        specifier: ^0.10.5
+        version: 0.10.5(quasar@2.17.0)
       '@slimfact/api':
         specifier: workspace:*
         version: link:../api
@@ -1988,6 +1988,11 @@ packages:
     peerDependencies:
       quasar: ^2.15.2
 
+  '@simsustech/quasar-components@0.10.5':
+    resolution: {integrity: sha512-fmevprWzhtJG1qtVojpNTA+fmuGZa2H108d05Y4Laf5jfzPZWW+Xa5VV5O3Dm2Hf1eDoE58xsCtDHAgDywJPAQ==}
+    peerDependencies:
+      quasar: ^2.15.2
+
   '@sindresorhus/is@5.6.0':
     resolution: {integrity: sha512-TV7t8GKYaJWsn00tFDqBw8+Uqmr8A0fRU1tvTQhyZzGv0sJCGRQL3JGMI3ucuKo3XIZdUP+Lx7/gh2t3lewy7g==}
     engines: {node: '>=14.16'}
@@ -7470,6 +7475,11 @@ snapshots:
       quasar: 2.17.0
       validator: 13.12.0
 
+  '@simsustech/quasar-components@0.10.5(quasar@2.17.0)':
+    dependencies:
+      quasar: 2.17.0
+      validator: 13.12.0
+
   '@sindresorhus/is@5.6.0': {}
 
   '@surma/rollup-plugin-off-main-thread@2.2.3':