Problem activating the plugin

Hi,

When I try to activate your plugin I receive

Fatal error: Declaration of BelaTimeIndex::afterUpdate() must be compatible with that of BelaIndex::afterUpdate() in ../plugins/better-extended-live-archive/classes/BelaTimeIndex.php on line 8

Could you please tell me what I need to do?
Thanks

https://wordpress.org/plugins/better-extended-live-archive/