After updating 5.6 to PHP 7. I was using HMVC implementation of Code Igniter and PHP upgrade started throwing following errors:-
A PHP Error was encountered Severity: Warning
Message: Declaration of MX_Loader::library($library, $params = NULL, $object_name = NULL) should be compatible with CI_Loader::library($library = '', $params = NULL, $object_name = NULL)
Filename: MX/Loader.php
Line Number: 143
A PHP Error was encountered Severity: Warning
Message: Declaration of MX_Loader::helper($helper) should be compatible with CI_Loader::helper($helpers = Array)
Filename: MX/Loader.php
Line Number: 0
A PHP Error was encountered Severity: Warning
Message: Declaration of MX_Loader::helpers($helpers) should be compatible with CI_Loader::helpers($helpers = Array)
Filename: MX/Loader.php
Line Number: 0
A PHP Error was encountered Severity: Warning
Message: Declaration of MX_Loader::language($langfile, $lang = '', $return = false) should be compatible with CI_Loader::language($file = Array, $lang = '')
Filename: MX/Loader.php
Line Number: 0
A PHP Error was encountered Severity: Warning
Message: Declaration of MX_Loader::_ci_get_component($component) should be compatible with & CI_Loader::_ci_get_component($component)
Filename: MX/Loader.php
Line Number: 0
A PHP Error was encountered Severity: Warning
Message: Declaration of MX_Lang::load($langfile, $lang = '', $return = false, $_module = NULL) should be compatible with CI_Lang::load($langfile = '', $idiom = '', $return = false, $add_suffix = true, $alt_path = '')
Filename: MX/Lang.php
Line Number: 70
A PHP Error was encountered Severity: Notice
Message: Only variables should be assigned by reference
Filename: core/Loader.php
Line Number: 257