diff --git a/composer.json b/composer.json
index 866935b..ab35a11 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,7 @@
         "slim/slim": "^3.12",
         "slim/twig-view": "^2.5",
         "slim/http-cache": "^0.4",
-        "twbs/bootstrap": "4.0.0",
+        "twbs/bootstrap": "4.3.1",
         "ajaxorg/ace": "1.4.5"
     },
     "scripts": {
diff --git a/composer.lock b/composer.lock
index 4aaff7c..3c6e2f3 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "ec5478929e85e7ef077c5b2687e4d531",
+    "content-hash": "8d3a5210f2dfa9f47c66356c5453251f",
     "packages": [
         {
             "name": "ajaxorg/ace",
@@ -532,16 +532,16 @@
         },
         {
             "name": "twbs/bootstrap",
-            "version": "v4.0.0",
+            "version": "v4.3.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/twbs/bootstrap.git",
-                "reference": "8a628b943cf31ca0a002c08af661a95772480225"
+                "reference": "8fa0d3010112dca5dd6dd501173415856001ba8b"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/twbs/bootstrap/zipball/8a628b943cf31ca0a002c08af661a95772480225",
-                "reference": "8a628b943cf31ca0a002c08af661a95772480225",
+                "url": "https://api.github.com/repos/twbs/bootstrap/zipball/8fa0d3010112dca5dd6dd501173415856001ba8b",
+                "reference": "8fa0d3010112dca5dd6dd501173415856001ba8b",
                 "shasum": ""
             },
             "replace": {
@@ -568,7 +568,7 @@
                 }
             ],
             "description": "The most popular front-end framework for developing responsive, mobile first projects on the web.",
-            "homepage": "https://getbootstrap.com",
+            "homepage": "https://getbootstrap.com/",
             "keywords": [
                 "JS",
                 "css",
@@ -579,7 +579,11 @@
                 "sass",
                 "web"
             ],
-            "time": "2018-01-18T18:29:48+00:00"
+            "support": {
+                "issues": "https://github.com/twbs/bootstrap/issues",
+                "source": "https://github.com/twbs/bootstrap/tree/v4.3.1"
+            },
+            "time": "2019-02-13T16:01:40+00:00"
         },
         {
             "name": "twig/twig",
@@ -656,5 +660,6 @@
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": [],
-    "platform-dev": []
+    "platform-dev": [],
+    "plugin-api-version": "2.6.0"
 }