diff --git a/app/assets/javascripts/issue_show/components/app.vue b/app/assets/javascripts/issue_show/components/app.vue
index cd569eb3045..b6eacf839b9 100644
--- a/app/assets/javascripts/issue_show/components/app.vue
+++ b/app/assets/javascripts/issue_show/components/app.vue
@@ -130,6 +130,10 @@ export default {
       required: false,
       default: true,
     },
+    lockVersion: {
+      type: Number,
+      required: true,
+    },
   },
   data() {
     const store = new Store({
@@ -141,6 +145,7 @@ export default {
       updatedByName: this.updatedByName,
       updatedByPath: this.updatedByPath,
       taskStatus: this.initialTaskStatus,
+      lock_version: this.lockVersion,
     });
 
     return {
@@ -214,6 +219,7 @@ export default {
         this.store.setFormState({
           title: this.state.titleText,
           description: this.state.descriptionText,
+          lock_version: this.state.lock_version,
           lockedWarningVisible: false,
           updateLoading: false,
         });
diff --git a/app/assets/javascripts/issue_show/stores/index.js b/app/assets/javascripts/issue_show/stores/index.js
index 32044d6da25..2b3903def6b 100644
--- a/app/assets/javascripts/issue_show/stores/index.js
+++ b/app/assets/javascripts/issue_show/stores/index.js
@@ -6,6 +6,7 @@ export default class Store {
       description: '',
       lockedWarningVisible: false,
       updateLoading: false,
+      lock_version: 0,
     };
   }
 
@@ -22,6 +23,7 @@ export default class Store {
     this.state.updatedAt = data.updated_at;
     this.state.updatedByName = data.updated_by_name;
     this.state.updatedByPath = data.updated_by_path;
+    this.state.lock_version = data.lock_version;
   }
 
   stateShouldUpdate(data) {
diff --git a/spec/helpers/issuables_helper_spec.rb b/spec/helpers/issuables_helper_spec.rb
index 03e3a72a82f..af319e5ebfe 100644
--- a/spec/helpers/issuables_helper_spec.rb
+++ b/spec/helpers/issuables_helper_spec.rb
@@ -190,6 +190,7 @@ describe IssuablesHelper do
         markdownDocsPath: '/help/user/markdown',
         markdownVersion: CacheMarkdownField::CACHE_COMMONMARK_VERSION,
         issuableTemplates: [],
+        lockVersion: issue.lock_version,
         projectPath: @project.path,
         projectNamespace: @project.namespace.path,
         initialTitleHtml: issue.title,
diff --git a/spec/javascripts/issue_show/components/app_spec.js b/spec/javascripts/issue_show/components/app_spec.js
index 2bd1b3996dc..9b2b6b670c3 100644
--- a/spec/javascripts/issue_show/components/app_spec.js
+++ b/spec/javascripts/issue_show/components/app_spec.js
@@ -43,6 +43,7 @@ describe('Issuable output', () => {
         initialTitleText: '',
         initialDescriptionHtml: 'test',
         initialDescriptionText: 'test',
+        lockVersion: 1,
         markdownPreviewPath: '/',
         markdownDocsPath: '/',
         projectNamespace: '/',
@@ -78,6 +79,7 @@ describe('Issuable output', () => {
         expect(formatText(editedText.innerText)).toMatch(/Edited[\s\S]+?by Some User/);
         expect(editedText.querySelector('.author-link').href).toMatch(/\/some_user$/);
         expect(editedText.querySelector('time')).toBeTruthy();
+        expect(vm.state.lock_version).toEqual(1);
       })
       .then(() => {
         vm.poll.makeRequest();
@@ -95,6 +97,7 @@ describe('Issuable output', () => {
 
         expect(editedText.querySelector('.author-link').href).toMatch(/\/other_user$/);
         expect(editedText.querySelector('time')).toBeTruthy();
+        expect(vm.state.lock_version).toEqual(2);
       })
       .then(done)
       .catch(done.fail);
@@ -255,15 +258,10 @@ describe('Issuable output', () => {
     describe('error when updating', () => {
       beforeEach(() => {
         spyOn(window, 'Flash').and.callThrough();
-        spyOn(vm.service, 'updateIssuable').and.callFake(
-          () =>
-            new Promise((resolve, reject) => {
-              reject();
-            }),
-        );
       });
 
       it('closes form on error', done => {
+        spyOn(vm.service, 'updateIssuable').and.callFake(() => Promise.resolve());
         vm.updateIssuable();
 
         setTimeout(() => {
@@ -276,6 +274,7 @@ describe('Issuable output', () => {
       });
 
       it('returns the correct error message for issuableType', done => {
+        spyOn(vm.service, 'updateIssuable').and.callFake(() => Promise.reject());
         vm.issuableType = 'merge request';
 
         Vue.nextTick(() => {
@@ -290,6 +289,20 @@ describe('Issuable output', () => {
           });
         });
       });
+
+      it('shows error mesage from backend if exists', done => {
+        const msg = 'Custom error message from backend';
+        spyOn(vm.service, 'updateIssuable').and.callFake(() =>
+          Promise.reject({ response: { data: { errors: msg } } }), // eslint-disable-line prefer-promise-reject-errors
+        );
+
+        vm.updateIssuable();
+        setTimeout(() => {
+          expect(window.Flash).toHaveBeenCalledWith(msg);
+
+          done();
+        });
+      });
     });
   });
 
@@ -420,6 +433,7 @@ describe('Issuable output', () => {
         .then(vm.$nextTick)
         .then(() => {
           expect(vm.formState.lockedWarningVisible).toEqual(true);
+          expect(vm.formState.lock_version).toEqual(1);
           expect(vm.$el.querySelector('.alert')).not.toBeNull();
         })
         .then(done)
diff --git a/spec/javascripts/issue_show/mock_data.js b/spec/javascripts/issue_show/mock_data.js
index 74b3efb014b..f4475aadb8b 100644
--- a/spec/javascripts/issue_show/mock_data.js
+++ b/spec/javascripts/issue_show/mock_data.js
@@ -8,6 +8,7 @@ export default {
     updated_at: '2015-05-15T12:31:04.428Z',
     updated_by_name: 'Some User',
     updated_by_path: '/some_user',
+    lock_version: 1,
   },
   secondRequest: {
     title: '<p>2</p>',
@@ -18,5 +19,6 @@ export default {
     updated_at: '2016-05-15T12:31:04.428Z',
     updated_by_name: 'Other User',
     updated_by_path: '/other_user',
+    lock_version: 2,
   },
 };