The Magento 2.0 has been developed for a long time, but I have some fear to migrate from 1.9 version.
My question is about:
It's safe to migrate old stores to Magento 2.0 or not?
You should definitely start looking into the migration to Magento2.
Security: Magento2 comes with all the security fixes Magento1 has. Magento2 will be more secure as it comes with different architecture and new technologies.
Stability: Eventually Magento2 is a lot stable than the initial builds. This is the reason every other merchant are migrating to Magento2. Here is the list of open issues. You can go through them in case you are looking for some specific issues. https://github.com/magento/magento2/issues
Modules: You may be knowing that you have to rewrite all the custom modules you have in Magento1. Regarding 3rd party modules most of them should be available in Magento Market place. Again you can browse Magento market place to check their availability.
Magento is about to go to 2.3 version. There are lots of stores running on Magento 2.
Different from Magento 1, you can see all the issues in the magento's github repository
Magento 2 has much more transparency then Magento 1
In terms of scalability, it supports much more transactions than Magento 1
In terms of modules, now is much more easy to check backward compatibility thing that was a big pain in magento 1.
Magento 2.x is being improved continuously and it is being maintained by a large community of developers. Magento team has launched its 2.2.2 version which is a stable release.
Also, Magento 1.x will stop getting any security patches or upgrades after some time.
There are many reasons why we should upgrade Magento 1.x stores to Magento 2.x.
Apart from above points, there are many others which prove that upgrading to Magento 2.x is a good decision.
Yes, It's safe to migrate old stores to Magento 2.0.
data-migration-tool you can migrate your old store to new Magento2 store.
This tool is only copied from your old store data. do not worry about security.
After the upgrade in Magento 2, your all core data are migrated in Magento2. Do not worry about stability.
Third-party modules are not migrated. because database table of that custom module is not available in Magento2.
If you want to migrate with the custom module that that particular extension install in Magento 2 and map that custom database table in migration tool.