diff --git a/.travis.yml b/.travis.yml
index 34a4e5f63..a23ea2b08 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,16 +9,6 @@ php:
   - '7.0'
   - '7.1'
 
-matrix:
-  include:
-  - php: '5.3'
-    dist: precise
-    sudo: required
-    env:
-    - PHPCS_VERSION=2.9.1
-    - LOCALE_GEN=1
-    - ENABLE_LDAP=1
-
 services:
   - mysql
   - postgresql
diff --git a/application/clicommands/WebCommand.php b/application/clicommands/WebCommand.php
index 20e1e9128..7277a1fd4 100644
--- a/application/clicommands/WebCommand.php
+++ b/application/clicommands/WebCommand.php
@@ -30,15 +30,6 @@ class WebCommand extends Command
      */
     public function serveAction()
     {
-        $minVersion = '5.4.0';
-        if (version_compare(PHP_VERSION, $minVersion) < 0) {
-            throw new IcingaException(
-                'You are running PHP %s, internal webserver requires %s.',
-                PHP_VERSION,
-                $minVersion
-            );
-        }
-
         $fork = $this->params->get('daemonize');
         $listen = $this->params->get('listen');
         $port = $this->params->get('port');
diff --git a/application/forms/Config/Resource/DbResourceForm.php b/application/forms/Config/Resource/DbResourceForm.php
index 89fe75f15..c270f7d91 100644
--- a/application/forms/Config/Resource/DbResourceForm.php
+++ b/application/forms/Config/Resource/DbResourceForm.php
@@ -46,7 +46,6 @@ class DbResourceForm extends Form
             $dbChoices['oci'] = 'Oracle (OCI8)';
         }
 
-        $offerSsl = false;
         $offerPostgres = false;
         $offerIbm = false;
         $offerMysql = false;
@@ -55,9 +54,6 @@ class DbResourceForm extends Form
             $offerPostgres = true;
         } elseif ($dbChoice === 'mysql') {
             $offerMysql = true;
-            if (version_compare(Platform::getPhpVersion(), '5.4.0', '>=')) {
-                $offerSsl = true;
-            }
         } elseif ($dbChoice === 'ibm') {
             $offerIbm = true;
         }
@@ -161,62 +157,60 @@ class DbResourceForm extends Form
                 'label'         => $this->translate('Persistent')
             )
         );
-        if ($offerSsl) {
+        $this->addElement(
+            'checkbox',
+            'use_ssl',
+            array(
+                'autosubmit'    => true,
+                'label'         => $this->translate('Use SSL'),
+                'description'   => $this->translate(
+                    'Whether to encrypt the connection or to authenticate using certificates'
+                )
+            )
+        );
+        if (isset($formData['use_ssl']) && $formData['use_ssl']) {
             $this->addElement(
-                'checkbox',
-                'use_ssl',
+                'text',
+                'ssl_key',
                 array(
-                    'autosubmit'    => true,
-                    'label'         => $this->translate('Use SSL'),
-                    'description'   => $this->translate(
-                        'Whether to encrypt the connection or to authenticate using certificates'
+                    'label'             => $this->translate('SSL Key'),
+                    'description'       => $this->translate('The client key file path')
+                )
+            );
+            $this->addElement(
+                'text',
+                'ssl_cert',
+                array(
+                    'label'             => $this->translate('SSL Certificate'),
+                    'description'       => $this->translate('The certificate file path')
+                )
+            );
+            $this->addElement(
+                'text',
+                'ssl_ca',
+                array(
+                    'label'             => $this->translate('SSL CA'),
+                    'description'       => $this->translate('The CA certificate file path')
+                )
+            );
+            $this->addElement(
+                'text',
+                'ssl_capath',
+                array(
+                    'label'             => $this->translate('SSL CA Path'),
+                    'description'       => $this->translate(
+                        'The trusted CA certificates in PEM format directory path'
                     )
                 )
             );
-            if (isset($formData['use_ssl']) && $formData['use_ssl']) {
-                $this->addElement(
-                    'text',
-                    'ssl_key',
-                    array(
-                        'label'             => $this->translate('SSL Key'),
-                        'description'       => $this->translate('The client key file path')
-                    )
-                );
-                $this->addElement(
-                    'text',
-                    'ssl_cert',
-                    array(
-                        'label'             => $this->translate('SSL Certificate'),
-                        'description'       => $this->translate('The certificate file path')
-                    )
-                );
-                $this->addElement(
-                    'text',
-                    'ssl_ca',
-                    array(
-                        'label'             => $this->translate('SSL CA'),
-                        'description'       => $this->translate('The CA certificate file path')
-                    )
-                );
-                $this->addElement(
-                    'text',
-                    'ssl_capath',
-                    array(
-                        'label'             => $this->translate('SSL CA Path'),
-                        'description'       => $this->translate(
-                            'The trusted CA certificates in PEM format directory path'
-                        )
-                    )
-                );
-                $this->addElement(
-                    'text',
-                    'ssl_cipher',
-                    array(
-                        'label'             => $this->translate('SSL Cipher'),
-                        'description'       => $this->translate('The list of permissible ciphers')
-                    )
-                );
-            }
+            $this->addElement(
+                'text',
+                'ssl_cipher',
+                array(
+                    'label'             => $this->translate('SSL Cipher'),
+                    'description'       => $this->translate('The list of permissible ciphers')
+                )
+            );
         }
 
         return $this;
diff --git a/library/Icinga/Chart/Donut.php b/library/Icinga/Chart/Donut.php
index 79230a6a6..8e6c58920 100644
--- a/library/Icinga/Chart/Donut.php
+++ b/library/Icinga/Chart/Donut.php
@@ -374,13 +374,7 @@ class Donut
 
     protected function encode($content)
     {
-        if (version_compare(PHP_VERSION, '5.4.0') >= 0) {
-            $replaceFlags = ENT_COMPAT | ENT_SUBSTITUTE | ENT_HTML5;
-        } else {
-            $replaceFlags = ENT_COMPAT | ENT_IGNORE;
-        }
-
-        return htmlspecialchars($content, $replaceFlags, 'UTF-8', true);
+        return htmlspecialchars($content, ENT_COMPAT | ENT_SUBSTITUTE | ENT_HTML5, 'UTF-8', true);
     }
 
     protected function renderAttributes(array $attributes)
diff --git a/library/Icinga/Data/Filter/Filter.php b/library/Icinga/Data/Filter/Filter.php
index 635de5660..f5d8bdf13 100644
--- a/library/Icinga/Data/Filter/Filter.php
+++ b/library/Icinga/Data/Filter/Filter.php
@@ -98,7 +98,7 @@ abstract class Filter
             }
         }
 
-        krsort($operators, version_compare(PHP_VERSION, '5.4.0') >= 0 ? SORT_NATURAL : SORT_REGULAR);
+        krsort($operators, SORT_NATURAL);
         foreach ($operators as $id => $operator) {
             $f = $filter->getById($id);
             if ($f->getOperatorName() !== $operator) {
diff --git a/library/Icinga/Protocol/Ldap/LdapConnection.php b/library/Icinga/Protocol/Ldap/LdapConnection.php
index 9a7346e91..5290894b3 100644
--- a/library/Icinga/Protocol/Ldap/LdapConnection.php
+++ b/library/Icinga/Protocol/Ldap/LdapConnection.php
@@ -427,10 +427,7 @@ class LdapConnection implements Selectable, Inspectable
     {
         $this->bind();
 
-        if ($query->getUsePagedResults()
-            && version_compare(PHP_VERSION, '5.4.0') >= 0
-            && $this->getCapabilities()->hasPagedResult()
-        ) {
+        if ($query->getUsePagedResults() && $this->getCapabilities()->hasPagedResult()) {
             return $this->runPagedQuery($query, $fields);
         } else {
             return $this->runQuery($query, $fields);
@@ -1156,11 +1153,7 @@ class LdapConnection implements Selectable, Inspectable
             $sequenceOf = '30' . str_pad(dechex($sequenceOfOctets), 2, '0', STR_PAD_LEFT) . $sequenceOf;
         }
 
-        if (version_compare(PHP_VERSION, '5.4.0') >= 0) {
-            return hex2bin($sequenceOf);
-        } else {
-            return pack('H*', $sequenceOf);
-        }
+        return hex2bin($sequenceOf);
     }
 
     /**
diff --git a/library/Icinga/Util/Json.php b/library/Icinga/Util/Json.php
index b41da82d5..98e013919 100644
--- a/library/Icinga/Util/Json.php
+++ b/library/Icinga/Util/Json.php
@@ -23,9 +23,7 @@ class Json
      */
     public static function encode($value, $options = 0, $depth = 512)
     {
-        if (version_compare(phpversion(), '5.4.0', '<')) {
-            $encoded = json_encode($value);
-        } elseif (version_compare(phpversion(), '5.5.0', '<')) {
+        if (version_compare(phpversion(), '5.5.0', '<')) {
             $encoded = json_encode($value, $options);
         } else {
             $encoded = json_encode($value, $options, $depth);
@@ -49,11 +47,7 @@ class Json
      */
     public static function decode($json, $assoc = false, $depth = 512, $options = 0)
     {
-        if (version_compare(phpversion(), '5.4.0', '<')) {
-            $decoded = json_decode($json, $assoc, $depth);
-        } else {
-            $decoded = json_decode($json, $assoc, $depth, $options);
-        }
+        $decoded = json_decode($json, $assoc, $depth, $options);
 
         if (json_last_error() !== JSON_ERROR_NONE) {
             throw new JsonDecodeException('%s: %s', static::lastErrorMsg(), var_export($json, true));
diff --git a/library/Icinga/Web/StyleSheet.php b/library/Icinga/Web/StyleSheet.php
index 63eee3647..21a69f252 100644
--- a/library/Icinga/Web/StyleSheet.php
+++ b/library/Icinga/Web/StyleSheet.php
@@ -80,10 +80,6 @@ class StyleSheet
      */
     public function __construct()
     {
-        // PHP had a rather conservative PCRE backtrack limit unless 5.3.7
-        if (version_compare(PHP_VERSION, '5.3.7') <= 0) {
-            ini_set('pcre.backtrack_limit', 1000000);
-        }
         $app = Icinga::app();
         $this->app = $app;
         $this->lessCompiler = new LessCompiler();
diff --git a/library/Icinga/Web/View.php b/library/Icinga/Web/View.php
index 7568a0a9c..2d5bb4cc3 100644
--- a/library/Icinga/Web/View.php
+++ b/library/Icinga/Web/View.php
@@ -58,11 +58,6 @@ class View extends Zend_View_Abstract
      */
     const CHARSET = 'UTF-8';
 
-    /**
-     * The flags we use for htmlspecialchars depend on our PHP version
-     */
-    private $replaceFlags;
-
     /**
      * Flag to register stream wrapper
      *
@@ -97,12 +92,6 @@ class View extends Zend_View_Abstract
             }
         }
 
-        if (version_compare(PHP_VERSION, '5.4.0') >= 0) {
-            $this->replaceFlags = ENT_COMPAT | ENT_SUBSTITUTE | ENT_HTML5;
-        } else {
-            $this->replaceFlags = ENT_COMPAT | ENT_IGNORE;
-        }
-
         parent::__construct($config);
     }
 
@@ -124,7 +113,7 @@ class View extends Zend_View_Abstract
      */
     public function escape($value)
     {
-        return htmlspecialchars($value, $this->replaceFlags, self::CHARSET, true);
+        return htmlspecialchars($value, ENT_COMPAT | ENT_SUBSTITUTE | ENT_HTML5, self::CHARSET, true);
     }
 
     /**
diff --git a/library/Icinga/Web/Widget/FilterEditor.php b/library/Icinga/Web/Widget/FilterEditor.php
index d8f2ff763..9d5f82619 100644
--- a/library/Icinga/Web/Widget/FilterEditor.php
+++ b/library/Icinga/Web/Widget/FilterEditor.php
@@ -668,7 +668,7 @@ class FilterEditor extends AbstractWidget
             }
         }
 
-        krsort($operators, version_compare(PHP_VERSION, '5.4.0') >= 0 ? SORT_NATURAL : SORT_REGULAR);
+        krsort($operators, SORT_NATURAL);
         foreach ($operators as $id => $operator) {
             $f = $filter->getById($id);
             if ($f->getOperatorName() !== $operator) {
diff --git a/modules/setup/application/locale/de_DE/LC_MESSAGES/setup.po b/modules/setup/application/locale/de_DE/LC_MESSAGES/setup.po
index 64ddfb8c8..17d2742d2 100644
--- a/modules/setup/application/locale/de_DE/LC_MESSAGES/setup.po
+++ b/modules/setup/application/locale/de_DE/LC_MESSAGES/setup.po
@@ -884,11 +884,9 @@ msgstr "Root DN"
 
 #: ../../../../modules/setup/library/Setup/WebWizard.php:556
 msgid ""
-"Running Icinga Web 2 requires PHP version 5.3.2. Advanced features like the "
-"built-in web server require PHP version 5.4."
+"Running Icinga Web 2 requires PHP version 5.4."
 msgstr ""
-"Der Betrieb von Icinga Web 2 erfordert die PHP-Version 5.3.2. Anspruchsvolle "
-"Funktionalitäten wie der eingebaute Webserver erfordern die PHP-Version 5.4."
+"Der Betrieb von Icinga Web 2 erfordert die PHP-Version 5.4."
 
 #: ../../../../modules/setup/library/Setup/Steps/ResourceStep.php:104
 msgid "SSL Cert"
diff --git a/modules/setup/application/locale/it_IT/LC_MESSAGES/setup.po b/modules/setup/application/locale/it_IT/LC_MESSAGES/setup.po
index 8a765f2c1..ec1d04b3c 100644
--- a/modules/setup/application/locale/it_IT/LC_MESSAGES/setup.po
+++ b/modules/setup/application/locale/it_IT/LC_MESSAGES/setup.po
@@ -862,11 +862,9 @@ msgstr "Root DN"
 
 #: /usr/share/icingaweb2/modules/setup/library/Setup/WebWizard.php:552
 msgid ""
-"Running Icinga Web 2 requires PHP version 5.3.2. Advanced features like the "
-"built-in web server require PHP version 5.4."
+"Running Icinga Web 2 requires PHP version 5.4."
 msgstr ""
-"Icinga Web 2 richiede PHP 5.3.2. Funzionalità avanzate come il web server "
-"integrato richiedono PHP 5.4."
+"Icinga Web 2 richiede PHP 5.4."
 
 #: /usr/share/icingaweb2/modules/setup/library/Setup/WebWizard.php:356
 msgid "Setup Icinga Web 2"
diff --git a/modules/setup/library/Setup/WebWizard.php b/modules/setup/library/Setup/WebWizard.php
index e5d406946..2181cab59 100644
--- a/modules/setup/library/Setup/WebWizard.php
+++ b/modules/setup/library/Setup/WebWizard.php
@@ -568,11 +568,10 @@ class WebWizard extends Wizard implements SetupWizard
         $set = new RequirementSet();
 
         $set->add(new PhpVersionRequirement(array(
-            'condition'     => array('>=', '5.3.2'),
+            'condition'     => array('>=', '5.4'),
             'description'   => mt(
                 'setup',
-                'Running Icinga Web 2 requires PHP version 5.3.2. Advanced features'
-                . ' like the built-in web server require PHP version 5.4.'
+                'Running Icinga Web 2 requires PHP version 5.4.'
             )
         )));