MigraShop is very good at this difficult work. We actually did a "retrogression" from 1.6.1 to 1.5.1 and though it was difficult it has worked out.
Probably not a one day solution for more difficult migrations, but well worth it when your site is having "issues".. I feel that as a simple cleanup process, this is as good a solution as you will find. Basically build a new Site with the Extensions you really need then let MigraShop do its work of moving you across the Rubicon.
January 4, 2012
Joseph migrated our Magento 1.1.8 database to Magento 1.6.1. He even migrated the grouped products.
He was very responsive and helpful throughout the process and did it all at a very reasonable cost.
I am very happy I found Joseph! I would highly recommend his services.
December 9, 2011
Joseph did a great job. Did the impossible by upgrading from 1.1 to 1.5. Great and thanks again!
October 23, 2011
I would like to give thumbs up to Joseph from Migrashop, when I thought i'ed never was be able to migrate my 1.3.4 database to the latest version he did it.
As i had to get some special wishes, he did it on his own server. The service afterwards was also very pleasant.
Thanks! you saved my webshop!
July 23, 2011