Update my WordPress / woo commerce site / Sever to the latest update

LetsEncrypt root certificate has expired so the web host said I need to also update curl/php-curl on the sever. I told him to go ahead and do this, However he said I also need to update the PHP Version and MYSQL, I've never done this before, also my Woocommerce / Wordpress is not up to date, So basically I need someone to update everything and get it working 100% I'm currently running: Wordpress WP version 4.9.18 WooCommerce version: WC version:3.2.5 MySQL version: 5.5.62 cURL version: 7.38.0, OpenSSL/1.0.1t Server info: Apache/2.4.10 PHP version: 7.0.33-1~dotdeb+8.1 Server is running on Debian 8 system One other problem: The Cart function on woo commerce is not allowing some people to check out correctly, I believe its a browser compatibility issue. I am running a number of plugins + the theme which will also need to be updated in WordPress for the site to run smoothly on the new version. Active plugins (25) Ultimate Addons for Visual Composer by Brainstorm Force – 3.16.21 Woocommerce Laybuy by Carl Bowden, Larry Watene – 3.2.2 – Not tested with the active version of WooCommerce Afterpay Gateway for WooCommerce by Afterpay – 3.2.2 Bambora APAC Online Plug-in for WooCommerce. by Bambora APAC – 1.2.2 – Not tested with the active version of WooCommerce Contact Form 7 by Takayuki Miyoshi – 5.0.1 Dynamic Featured Image by Ankit Pokhrel – 3.6.5 reCaptcha Pro by BestWebSoft by BestWebSoft – 1.62 WPBakery Page Builder by Michael M - [login to view URL] – 5.4.5 Max Mega Menu by [login to view URL] – 2.5.2 PHPlist by Jesse Heap – 1.7 Porto Theme - Functionality by SW-THEMES – 1.0.5 Redirection by John Godley – 3.5 Slider Revolution by ThemePunch – 5.4.6.4 SSL Insecure Content Fixer by WebAware – 2.7.0 W3 Total Cache by Frederick Townes – 0.9.7 WooCommerce Waitlist Premium by XootiX – 1.5 – Not tested with the active version of WooCommerce WooCommerce Cash On Pickup by Marian Kadanka – 1.4.4 Woocommerce Calculate Shipping In Product Page by enhancewc – 1.0.5 – Not tested with the active version of WooCommerce WooCommerce Advanced Bulk Edit by George Iron – 4.4.5-beta2 WooCommerce Advanced Product Labels by Jeroen Sormani – 1.1.4 – 1.1.8 is available WooCommerce Advanced Shipping by Jeroen Sormani – 1.0.14 WooCommerce by Automattic – 3.2.5 Yoast SEO by Team Yoast – 8.3 WP Sitemap Page by Tony Archambeau – 1.6.1 YITH WooCommerce Ajax Search by YITHEMES – 1.5.5 Theme Name: Porto Child Version: 1.1 Author URL: [login to view URL] Child theme: Parent theme name: Porto Parent theme version: 4.2 Parent theme author URL: [login to view URL] WooCommerce support: