diff --git a/core/INSTALL.txt b/core/INSTALL.txt
index 6379cfa1fcd..eef7efb09bb 100644
--- a/core/INSTALL.txt
+++ b/core/INSTALL.txt
@@ -56,7 +56,7 @@ Drupal requires:
     compatible drop-in replacement for MySQL.
   - Percona Server 5.7.8 (or greater) (http://www.percona.com/). Percona
     Server is a backwards-compatible replacement for MySQL.
-  - PostgreSQL 9.1.2 (or greater) (http://www.postgresql.org/).
+  - PostgreSQL 10 (or greater) (http://www.postgresql.org/).
   - SQLite 3.26 (or greater) (http://www.sqlite.org/).
 
 For more detailed information about Drupal requirements, including a list of
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
index 65577d2cc8f..056105e25df 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php
@@ -11,6 +11,15 @@ use Drupal\Core\Database\DatabaseNotFoundException;
  */
 class Tasks extends InstallTasks {
 
+  /**
+   * Minimum required PostgreSQL version.
+   *
+   * The contrib extension pg_trgm is supposed to be installed.
+   *
+   * @see https://www.postgresql.org/docs/10/pgtrgm.html
+   */
+  const PGSQL_MINIMUM_VERSION = '10';
+
   /**
    * {@inheritdoc}
    */
@@ -49,7 +58,7 @@ class Tasks extends InstallTasks {
    * {@inheritdoc}
    */
   public function minimumVersion() {
-    return '9.1.2';
+    return static::PGSQL_MINIMUM_VERSION;
   }
 
   /**
@@ -133,42 +142,38 @@ class Tasks extends InstallTasks {
    * Unserializing does not work on Postgresql 9 when bytea_output is 'hex'.
    */
   public function checkBinaryOutput() {
-    // PostgreSQL < 9 doesn't support bytea_output, so verify we are running
-    // at least PostgreSQL 9.
     $database_connection = Database::getConnection();
-    if (version_compare($database_connection->version(), '9') >= 0) {
+    if (!$this->checkBinaryOutputSuccess()) {
+      // First try to alter the database. If it fails, raise an error telling
+      // the user to do it themselves.
+      $connection_options = $database_connection->getConnectionOptions();
+      // It is safe to include the database name directly here, because this
+      // code is only called when a connection to the database is already
+      // established, thus the database name is guaranteed to be a correct
+      // value.
+      $query = "ALTER DATABASE \"{$connection_options['database']}\" SET bytea_output = 'escape';";
+      try {
+        $database_connection->query($query);
+      }
+      catch (\Exception $e) {
+        // Ignore possible errors when the user doesn't have the necessary
+        // privileges to ALTER the database.
+      }
+
+      // Close the database connection so that the configuration parameter
+      // is applied to the current connection.
+      Database::closeConnection();
+
+      // Recheck, if it fails, finally just rely on the end user to do the
+      // right thing.
       if (!$this->checkBinaryOutputSuccess()) {
-        // First try to alter the database. If it fails, raise an error telling
-        // the user to do it themselves.
-        $connection_options = $database_connection->getConnectionOptions();
-        // It is safe to include the database name directly here, because this
-        // code is only called when a connection to the database is already
-        // established, thus the database name is guaranteed to be a correct
-        // value.
-        $query = "ALTER DATABASE \"" . $connection_options['database'] . "\" SET bytea_output = 'escape';";
-        try {
-          $database_connection->query($query);
-        }
-        catch (\Exception $e) {
-          // Ignore possible errors when the user doesn't have the necessary
-          // privileges to ALTER the database.
-        }
-
-        // Close the database connection so that the configuration parameter
-        // is applied to the current connection.
-        Database::closeConnection();
-
-        // Recheck, if it fails, finally just rely on the end user to do the
-        // right thing.
-        if (!$this->checkBinaryOutputSuccess()) {
-          $replacements = [
-            '%setting' => 'bytea_output',
-            '%current_value' => 'hex',
-            '%needed_value' => 'escape',
-            '@query' => $query,
-          ];
-          $this->fail(t("The %setting setting is currently set to '%current_value', but needs to be '%needed_value'. Change this by running the following query: <code>@query</code>", $replacements));
-        }
+        $replacements = [
+          '%setting' => 'bytea_output',
+          '%current_value' => 'hex',
+          '%needed_value' => 'escape',
+          '@query' => $query,
+        ];
+        $this->fail(t("The %setting setting is currently set to '%current_value', but needs to be '%needed_value'. Change this by running the following query: <code>@query</code>", $replacements));
       }
     }
   }
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
index 9eb681bc53a..fd4579b62fa 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
@@ -380,7 +380,7 @@ EOD;
     }
 
     if (!empty($field['unsigned'])) {
-      // Unsigned data types are not supported in PostgreSQL 9.1. In MySQL,
+      // Unsigned data types are not supported in PostgreSQL 10. In MySQL,
       // they are used to ensure a positive number is inserted and it also
       // doubles the maximum integer size that can be stored in a field.
       // The PostgreSQL schema in Drupal creates a check constraint
@@ -706,7 +706,7 @@ EOD;
    * {@inheritdoc}
    */
   public function indexExists($table, $name) {
-    // Details http://www.postgresql.org/docs/9.1/interactive/view-pg-indexes.html
+    // Details https://www.postgresql.org/docs/10/view-pg-indexes.html
     $index_name = $this->ensureIdentifiersLength($table, $name, 'idx');
     // Remove leading and trailing quotes because the index name is in a WHERE
     // clause and not used as an identifier.