title: How to downgrade from EF6 to EF5
body: <p>I have a windows application which used to use EF 5 Code first.</p>
  
  <p>This application is being used by 100+ clients.</p>
  
  <p>Recently, I upgraded EF5 to EF6.</p>
  
  <p>The upgrade is deployed to 100 clients.</p>
  
  <p>The migration history table of EF5 was also upgraded to EF6, which introduced a new primary key column 'ContextKey'.</p>
  
  <p>Now I want to revert EF6 to EF5.</p>
  
  <p>I have a script to drop 'ContextKey' from the migration table.</p>
  
  <p>But I can not manually execute to 100+ clients.</p>
  
  <p>What would be the best way to downgrade from EF6 to EF5?</p>