diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index a04a65e..12cd391 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -165,7 +165,7 @@
 		}
 
 		// Now we set the character set and that's all
-		return $this->db_set_charset($this->char_set, $this->dbcollat);
+		return $this->db_set_charset($this->char_set);
 	}
 
 	// --------------------------------------------------------------------
@@ -177,9 +177,9 @@
 	 * @param	string
 	 * @return	bool
 	 */
-	public function db_set_charset($charset, $collation = '')
+	public function db_set_charset($charset)
 	{
-		if (method_exists($this, '_db_set_charset') && ! $this->_db_set_charset($charset, $collation))
+		if (method_exists($this, '_db_set_charset') && ! $this->_db_set_charset($charset))
 		{
 			log_message('error', 'Unable to set database connection charset: '.$charset);
 
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index 071ce43..ba646d2 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -144,10 +144,9 @@
 	 * Set client character set
 	 *
 	 * @param	string
-	 * @param	string
 	 * @return	bool
 	 */
-	protected function _db_set_charset($charset, $collation)
+	protected function _db_set_charset($charset)
 	{
 		return @mysql_set_charset($charset, $this->conn_id);
 	}
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index e84b834..f38b94c 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -144,10 +144,9 @@
 	 * Set client character set
 	 *
 	 * @param	string
-	 * @param	string
 	 * @return	bool
 	 */
-	protected function _db_set_charset($charset, $collation)
+	protected function _db_set_charset($charset)
 	{
 		return @mysqli_set_charset($this->conn_id, $charset);
 	}
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 5bea350..1f148e9 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -68,6 +68,8 @@
    -  Added a constructor to the DB_result class and moved all driver-specific properties and logic out of the base DB_driver class to allow better abstraction.
    -  Removed limit() and order_by() support for UPDATE and DELETE queries in PostgreSQL driver. Postgres does not support those features.
    -  Removed protect_identifiers() and renamed _protect_identifiers() to it instead - it was just an alias.
+   -  MySQL and MySQLi drivers now require at least MySQL version 5.1.
+   -  db_set_charset() now only requires one parameter (collation was only needed due to legacy support for MySQL versions prior to 5.1).
 
 -  Libraries
 
@@ -141,7 +143,7 @@
 -  Fixed a bug in PDO's _version() method where it used to return the client version as opposed to the server one.
 -  Fixed a bug in PDO's insert_id() method where it could've failed if it's used with Postgre versions prior to 8.1.
 -  Fixed a bug in CUBRID's affected_rows() method where a connection resource was passed to cubrid_affected_rows() instead of a result.
--  Fixed a bug (#638) - db_set_charset() ignored its arguments and always used the configured charset and collation instead.
+-  Fixed a bug (#638) - db_set_charset() ignored its arguments and always used the configured charset instead.
 -  Fixed a bug (#413) - Oracle's error handling methods used to only return connection-related errors.
 -  Fixed a bug (#804) - Profiler library was trying to handle objects as strings in some cases, resulting in warnings being issued by htmlspecialchars().
 -  Fixed a bug (#1101) - MySQL/MySQLi result method field_data() was implemented as if it was handling a DESCRIBE result instead of the actual result set.