WP_Import::bump_request_timeout()

( ! ) Strict standards: Declaration of WP_Import::bump_request_timeout() should be compatible with WP_Importer::bump_request_timeout($val)

Please check

wp-content/plugins/wordpress-importer/wordpress-importer.php

line 1110

function bump_request_timeout()

change on this

function bump_request_timeout( $val )