Problem with fundraising and sandbox (mode sandbox)

Hello,

As mentioned to this thread :

https://premium.wpmudev.org/forums/topic/cannot-test-paypal-using-fundrasing-plugin

Paypal changed : the sandbox now requires TLS 1.2 for all requests.

Miniu solution to change the core of wordpress /
curl_setopt ( $handle, CURLOPT_SSLVERSION, 6 );
somewhere on line 131 in wp-includes/class-wp-http-curl.php

seems to be a solution ... but it doesn't work to my configuration ... I ve upgraded php to 7.0 version ... but my version of curl is still: 7.21.0 .. and it seems to be not enough ...

so what could be a correct solution for my case ?

Thx lot

Fulgence