osCommerce 2.2-MS2, PHP Upgrade

We require an upgrade of our osCommerce 2.2-MS2, running on PHP 5.2.17, patch to current PHP version 5.6. Goal to upgrade to osCommerce 2.3. Multiple addons, with extensive custom coding. Addons: This may not be a complete list of addons: PayPal [login to view URL] Super Download Store (w/custom upload capability) Admin With Access Levels 2.1 (we have sales people, client service people, researchers, supervisor and admin levels) Bitcoin Via Bitpay Will Call With Credit Card Info Credit/Gift Voucher/Coupons 5.13 + all patches Edit Orders 1.59 (Order editor) OSC-Affiliate 2.02 Single Page Checkout (for ezdd214) Step By Step Manual Order entry v1.4 SEO URLs Reviews, Add Review (for admin, custom) Manage Quiries (basically management reports, which we will want to automate in the future) Recover Cart Sales Support System (Ticket based, custom to work with our osCommerce), includes FAQ/HelpDesk Sales Report Mail Beeze (used for Order completion prompts to customers, pay, complete form, request review after delivery. They are now subscription based, and our need is limited. I prefer what we have either the current fnctionality, or some modification of Mailmanager with a cron job for Mailmanager) Login - Secret Questions (custom) Live CHAT Orders Comment Orders Status Assignment Record Retrieval Estimator (custom) VetRec Card Tools (custom) Site Monitor API Settings (custom) Better Together [login to view URL] Mail Manager [login to view URL] Batch Print Center [login to view URL] Canned Order Comments [login to view URL] Admin Comments Toolbar [login to view URL] Super Download Store (w/custom upload capability) [login to view URL] Fancier Invoice [login to view URL] [login to view URL] Manual Payment [login to view URL] FedEx and USPS shipping through [login to view URL], with barcode scanning capability (custom). Our researcher scans the packing slip, and the appropriate shipping label is created. and custom form integration/processing depending on service ordered.