If you upgrade Jigoshop to the latest version on servers which still use PHP under 5.3., your shop will stop to work and will receive this error:
Parse error: syntax error, unexpected T_STRING in /home/(username)/(domain name)/wp-content/plugins/jigoshop/plugins/jigoshop-web-optimization-system/jigoshop-web-optimization.php on line 32
Of course, the best is to ask your hosting company to upgrade PHP at least to 5.3. version, as this is now the minimum requirement for Jigoshop, but if this is not possible go by ftp at wp-content/plugins/jigoshop/plugins/jigoshop-web-optimization-system and edit jigoshop-web-optimization.php.
Comment the line which create the problem:
so, it will look as:
// new \Jigoshop\Web\Optimization();
Can download the file from here and replace the original one from wp-content/plugins/jigoshop/plugins/jigoshop-web-optimization-system: Changed jigoshop-web-optimization.php
You will not benefit of the new feature for minifying CSS and JS of Jigoshop, but your shop will be functional again, at least until your host will upgrade the PHP on the server.