Is it possible to install a theme form magento 2.1 to magento 2.2.3 ?
If possible, how to do that? tell me guys. I need to use the old paid theme in latest magento 2.2.3
1) Is it possible to install a theme compatible with
Magento 2.1 and not with
Magento 2.2.3 ?
Look if your theme is compatible with
Magento 2.2.3 otherwise if it's not, don't install it, you will have errors, if you bought it contact the editor to download the lastest version
2) In a case that you have already made changes in this theme:
I don't recommend you this solution but try to install it in a test project instance but, prepare you to debug several errors !, the version of Magento changes between the different versions and a developper of that theme was based on old version and the code is not the same so it doesn't necessarily work with the new versions you understand ?
What I advise you is to recover all your custom theme modifications, install the version of the theme that is compatible then merge your changes, it takes less time and it avoids the erreors that you dont expect. without this method you go straight to the horrible errors !
Problem solved..! I had just upgrade to new version Magento Upgrade Easy Tutorial