PHP warning, is this thing i need to worry

Application Version - e.g., OJS

php warning alot of this line

PHP Warning: Declaration of CustomBlockPlugin::getBlockContext() should be compatible with BlockPlugin::getBlockContext($contextId = NULL) in /home/publisher/public_html/ojs/plugins/generic/customBlockManager/ on line 0

PHP Warning: Use of undefined constant STATISTICS_DIMENSION_ARTICLE_ID - assumed ‘STATISTICS_DIMENSION_ARTICLE_ID’ (this will throw an Error in a future version of PHP) in /home/publisher/public_html/ojs/plugins/generic/recommendByAuthor/ on line 90, referer:

what can i do to reduce this warning?

the front end system is working fine.