SharePoint 2013 Upgrade Path

The following picture represents the different upgrade options for different SharePoint versions.

While upgrading following are the questions that are frequently asked

1. Can I upgrade from 2003 – 2013? The answer is no direct upgrade possible and it would be a very painful experience – better to re-design and redo in 2013.

2. Can I upgrade from 2007 - 2013.The answer again is no direct upgrade possible. You need to go from 2007 to 2010 to 2013. 
So what about the licenses then. Do I need to purchase both licenses?

You don't need to purchase both licensed. You can buy a 2013 license, downgrade to 2010 perform the 2007 to 2010 upgrade and then upgrade the license to 2013.

3. What care do I need to take to upgrade from 2010 – 2013?

There should be no other SharePoint version to be present on the Server that has SharePoint 2013.

Project databases – 4 Databases gets merged to one 
Access databases – B2B upgrade happens only. 

 Unsupported Databases are as follows

• Configuration Database
  
• Search Index 
  
• User Profile Sync  
  

For Authentication Upgrade from Windows Classis to Windows Claims Authentication in SharePoint 2010 environment before upgrading to SharePoint 2013.

For Forms Auth Support – Ensure Provider installed with same name before database attachment. 

Deferred Site Collection Upgrade allows existing 2010 site collections to work unchanged in 2013.  Existing customizations work Unsupported features in 14 mode 2010. The following is the fallback behaviour of the features.

Other things to be taken care of are as follows

• Web Analytics – Remove the feature as Web Analytics Services is not supported in 15 mode
• Replace 2010 Office Web Applications with Web Server Functionality 
• PowerPoint broadcast sites to be removed and use Lync instead 
• Upgrade Project Web Access sites to 15 mode
  

In the Site Collection Upgradation features there is an option to try a demo upgrade as shown below.

Both 14 and 15 mode exists side by side.