Yes Check it.
take a look here
	
	
		
			
			
				
				End-user documentation for XenForo
				
					
						
							
						
					
					xenforo.com
				
 
			 
		 
	 
Note :
"It is vital that you backup your site before upgrading to XenForo 2. You 
cannot downgrade after the upgrade starts. The 
only method of downgrading will be to restore from a backup."