class-wc-geo-ip.php in woocommerce plugin

I run my wp multi-site installation website with woocommerce enabled under php 7.0 and suddenly faced to following issue on screen:

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Warning: fread() expects parameter 2 to be integer, string given in /home1/simitar/public_html/wp/wp-content/plugins/woocommerce/includes/class-wc-geo-ip.php on line 1392
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Despite this error, the whole site appears to work normaly, except always displaying the above error line.

I don’t know how to get rid of this. I already have reinstalled woocommerce but don’t succeeded. I have no clue where to start from.

Could someone please help me on this?

Thank you in advance.

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