Infragistics

Widget-fixer works by recalculating the string lengths of the widget strings and updating 
the relevant numbers in the database so that your widgets will load again.
Disclaimer 
This plugin is provided “as is.” It is free software licensed under the terms of the [GNU General Public License 2.0 (GPL)] (http://www.gnu.org/licenses/gpl.html “GNU General Public License 2.0”). It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Infragistics is not liable for any damages or losses.

Widget Fixer

Widget-fixer fixes your widgets after you change to a new siteurl.

MembershipWorks

If you ever change the Site Address under the WordPress settings, you may notice that all the links in your pages and posts may still use the old site url. This plugin plugin migrates all those urls in your WordPress database when you change the Site Address, without requiring the Search Replace DB script.
Site Address Migrator updates all links matching the old Site Address in:
<ul>
<li>Description, content and excerpts of all posts, pages and media (including custom types)</li>
<li>Post and page option fields</li>
<li>Comments and comment option fields</li>
<li>Post category and tag descriptions</li>
<li>User descriptions</li>
<li>User website fields</li>
<li>WordPress and widget option fields</li>
</ul>
Site Address Migrator will update links inside serialized data correctly. Site Address Migrator will also match links when the protocol does not match the Site Address (eg. the link uses “https://” instead of “http://”, or if it is protocol-relative “//”). The protocol used for the original link will be honored (ie. if the link was “https://”, it will remain “https://” even if the Site Address is given as “http://”).
Warning: Make sure you have access to the new site domain before updating the Site Address, and double check for spelling errors! Entering the wrong site address can prevent you from accessing WordPress again without manually fixing the MySQL database entries. Backup your MySQL database if possible.
This plugin is not designed for, and has not been tested for Multi-Site installs.

Site Address Migrator

Updates urls in pages, posts, comments, descriptions, widgets and options when Site Address (Site URL) is changed.

Widget Fixer vs Site Address Migrator