Ok, I figured out that I can rename the schema in LLBLGen just by right clicking on that. So I tried doing that in the catalog before refreshing in 2.6 Now, I'm getting this exception:
An item with the same key has already been added.
-----[Core exception]--------------------
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
at SD.LLBLGen.Pro.ApplicationCore.Entities.EntityRelationCollection.BuildCacheForContains()
at SD.LLBLGen.Pro.ApplicationCore.Entities.EntityContainer.ConstructRelations(EntityDefinition entityToUpdate, Int32 recursionDepth)
at SD.LLBLGen.Pro.ApplicationCore.CatalogRefresher.MigrateEntities()
at SD.LLBLGen.Pro.ApplicationCore.CatalogRefresher.MigrateProjectToNewCatalog(Boolean isUnattended, SelectTargetsForOrphanedElementsCallBack targetSelectCallBack)
at SD.LLBLGen.Pro.Gui.Forms.MainWindow.RefreshCatalogs(Boolean unattended, Hashtable catalogsToRefresh)
at SD.LLBLGen.Pro.Gui.Forms.MainWindow.RefreshAllCatalogs(Boolean unattended)
at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
at System.Windows.Forms.ToolStripMenuItem.OnClick(EventArgs e)
at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
at System.Windows.Forms.ToolStripDropDown.OnMouseUp(MouseEventArgs mea)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ToolStrip.WndProc(Message& m)
at System.Windows.Forms.ToolStripDropDown.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
This is final build for version 2.6.