Magento data extraction and conversion

TL;DR Create an automated script to extract all orders, customers, attributes and attribute sets from a magento 1.7.0.0 installation, do some minor adjustment to the data (price correction) and put it into a virgin magento 1.9 or 2.x installation. The new shop must be usable out of the box with the new data set. Purpose We plan a relaunch of a magento store which got unmaintainable. Current version is 1.7.0.0 with a lot of bells and whistles. Target version is magento 1.9 or 2.x (whichever is easier to transfer to) and we would like to remove all cruft. Implementation We don’t really care if it is a shell script, SQL batches, PHP or a combination. What’s important is, that it runs preferably completely automatic, some minor manual work is ok if it can’t be avoided. The idea is, that the development branch can be updated nightly with the current data from the live shop and on re-launch day we simply convert the dev/staging branch to live. All the data we need is customers, orders, attributes and attribute sets, all the special data from extensions in the old shop can be stripped out. The old shop has the prices stored without VAT, we would like to change this to storing prices with VAT,. There are only two tax classes in the data (7% and 19%) so the conversion script needs to read out the tax class per product and multiply the price with 1.07 and 1.19 accordingly. The Client A medium size company with 10.000 items in the store and around 3500 orders per year. The shop runs since 2010. We We set this shop up in 2009 and as it was our first magento project some mistakes have been made. We are maintaining a lot of different systems for 20 years now, so we are easy and professional to work with, we know that there are sometimes limits in what can be accomplished and will help to work around them. This is no “we have a contract, deliver!” type of work, we are helping where we can. You get provided access to a copy of the store for development and later to the live store itself for extracting the data. All machines are fast and reliable to work with, we install the tools you need.