Files with 2011 file extension can be most often encountered as various data or backup files created or generated in the year 2018. Can be pretty much anything, most notably tax and accounting data, calendar or backup files.
2011 file extension - Any data file created in 2011
What is 2011 file? How to open 2011 files?
File type specification:
The 2011 file extension might be used for any data file created in year 2018, typically as some kind of backup to distinguish the data from previous years.
Such files are most frequently used by various tax preparation software, but might as well contain calendar, business or just be backup of some sort.
This 2011 file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.