When you change your application to use an upgraded version of the UltraLite runtime files (for example, when you move from UltraLite version 11 to version 12) you will most likely need to rebuild your application and re-link with the required UltraLite runtime libraries or assemblies. When you link with a new version of the UltraLite libraries, you should be sure to deploy all updated versions of the UltraLite files as described above. Note also that UltraLite clients must closely match with UltraLite engines (the major versions must match). See Upgrading databases created with previous versions of UltraLite.