I'm confused

I accidentally deleted the contents of a table in my SQL database (no transaction!!)

So, we restore the MDF/LDF files, and try to attach these to the SQL server under a different name.

I get this message:

The database cannot be opened because it is version 869, This server support version 782 and earlier, a downgrade path is not supported.

i'm using SQL Express V2014 (12.0.2269)

The funny thing is that de MDF/LDF database is created with the same server, it is just a restore forpm backup.

So, How can I access this backup?

thanks for any help.