Some have used php5.6 successfully, but php 5.5 is what has been tested, and approved for the script.

Thank you

OK updated from 1.8.0 (working) to 1.8.4 by manual update pack and get the following error
Error details: Type: Exception Message: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'key' in 'where clause' File: /home/scseals/public_html/ox/ow_core/database.php Line: 723 Trace: #0 /home/scseals/public_html/ox/ow_core/database.php(723): PDOStatement->execute() #1 /home/scseals/public_html/ox/ow_core/database.php(308): OW_Database->execute('SELECT * FROM o...', Array) #2 /home/scseals/public_html/ox/ow_core/base_dao.php(114): OW_Database->queryForObject('SELECT * FROM o...', 'BOL_Theme', Array, 86400, Array) #3 /home/scseals/public_html/ox/ow_system_plugins/base/bol/theme_dao.php(111): OW_BaseDao->findObjectByExample(Object(OW_Example), 86400, Array) #4 /home/scseals/public_html/ox/ow_system_plugins/base/bol/theme_service.php(485): BOL_ThemeDao->findByKey('simplicity') #5 /home/scseals/public_html/ox/ow_core/theme_manager.php(66): BOL_ThemeService->getThemeObjectByKey('simplicity', false) #6 /home/scseals/public_html/ox/ow_core/application.php(154): OW_ThemeManager->initDefaultTheme(false) #7 /home/scseals/public_html/ox/index.php(54): OW_Application->init() #8 {main}
Any ideas?

Update has not been succcessfully completed, you need to restore your backup and run the update again. 

Than ks

Problem was 3rd party plug in, email invite members, needed to be re installed - now that it is running and updated, moving from Arvixe

php 5.6 is the highest you can use without having issues. From other forum post; there have been a few that ventured to try php 7, but found functionality issues.