I tried to upgrade an Umbraco 4.7.1 Websiute to version 4.8. 

In one custom Codefile I get this error:

"The project currently contains references to more than one version of interfaces, a direct reference to version 1.0.4583.15472 and an indirect reference (through 'umbraco.MacroEngines.DynamicNode.GetProperty') to version 1.0.4583.15505"

In the bin folder there is a interfaces.dll with version 1.0.4583.15472. I don't now where I can found the version 1.0.4583.15505?

This Error raises an other one in the same code line:

"Overload resolution failed because no accessible 'Where' can be called with theses arguments...

The code looks as follows:

Return BannerContainer.Descendants("ProjectX_Banner").Items.Where(Function(x) x.GetProperty("zone").Value = _ZoneID _
  And Not String.IsNullOrEmpty(x.GetProperty("bannerActivateDate").Value) _
  And Not String.IsNullOrEmpty(x.GetProperty("bannerExpiryDate").Value) _
  And ParseDate(x.GetProperty("bannerExpiryDate").Value) > Date.Now _
  And Mastertools.Util.IsTrue(x.GetProperty("bannerIsPaid").Value)) _
 .OrderBy(Function(x) CDate(x.GetProperty("bannerActivateDate").Value))

On this code File we have these Imports:

Imports System.Xml
Imports DigibizTree
Imports TheFarm.Umbraco.EmbeddedContent
Imports uComponents.Core.DataTypes.UrlPicker.Dto
Imports umbraco.cms.businesslogic.media
Imports umbraco.MacroEngines
Imports umbraco.NodeFactory

The workaround for using the uComponents.Core (move the old Lucene.dll to a legacy folder as explaind in 'Upgrading to Umbraco 4.8 breaks support for uComponents') has been applied allready. 

Thanks for any help.