Umbraco version: 7.6.4 Courier: 3.1.3

Any attempts to publish content throws the following exception:

2017-07-27 09:07:44,374 [26] ERROR Umbraco.Courier.Core.BackgroundTaskRunner - [Thread 26] An error occurred consuming task
System.Web.Services.Protocols.SoapException: System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> Umbraco.Courier.Core.Exceptions.RetrieveException: Error retrieving item [a33f7a5c-da5b-4c69-a182-69b903857c38] from provider [d8e6ad83-e73a-11df-9492-0800200c9a66]. ---> NHibernate.Exceptions.GenericADOException: could not initialize a collection batch: [Umbraco.Courier.Persistence.V6.NHibernate.EntityClasses.UmbracoNode.ChildRelations#System.Object[]][SQL: SELECT childrelat0_.parentId as parentId2_, childrelat0_.id as id2_, childrelat0_.id as id125_1_, childrelat0_.comment as comment125_1_, childrelat0_.datetime as datetime125_1_, childrelat0_.parentId as parentId125_1_, childrelat0_.childId as childId125_1_, childrelat0_.relType as relType125_1_, umbracorel1_.id as id126_0_, umbracorel1_.alias as alias126_0_, umbracorel1_.childObjectType as childObj3_126_0_, umbracorel1_.dual as dual126_0_, umbracorel1_.name as name126_0_, umbracorel1_.parentObjectType as parentOb6_126_0_, umbracorel1_.typeUniqueId as typeUniq7_126_0_ FROM umbracoRelation childrelat0_ left outer join umbracoRelationType umbracorel1_ on childrelat0_.relType=umbracorel1_.id WHERE childrelat0_.parentId in (?, ?, ?, ?)] ---> System.Data.SqlClient.SqlException: Invalid column name 'typeUniqueId'.
   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at System.Data.SqlClient.SqlDataReader.TryConsumeMetaData()
   at System.Data.SqlClient.SqlDataReader.get_MetaData()
   at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
   at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)
   at NHibernate.AdoNet.AbstractBatcher.ExecuteReader(IDbCommand cmd)
   at NHibernate.Loader.Loader.GetResultSet(IDbCommand st, Boolean autoDiscoverTypes, Boolean callable, RowSelection selection, ISessionImplementor session)
   at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)
   at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)
   at NHibernate.Loader.Loader.LoadCollectionBatch(ISessionImplementor session, Object[] ids, IType type)
   --- End of inner exception stack trace ---
   at NHibernate.Loader.Loader.LoadCollectionBatch(ISessionImplementor session, Object[] ids, IType type)
   at NHibernate.Event.Default.DefaultInitializeCollectionEventListener.OnInitializeCollection(InitializeCollectionEvent event)
   at NHibernate.Impl.SessionImpl.InitializeCollection(IPersistentCollection collection, Boolean writing)
   at NHibernate.Collection.AbstractPersistentCollection.Initialize(Boolean writing)
   at NHibernate.Collection.Generic.PersistentGenericSet`1.Iesi.Collections.Generic.ISet<T>.Union(ISet`1 a)
   at Umbraco.Courier.Persistence.V6.NHibernate.Helpers.RelationHelper.GetAllRelations(UmbracoNode node)
   at Umbraco.Courier.Persistence.V6.NHibernate.Persisters.ContentItemPersister`1.CreateAndMapProperties(ItemIdentifier itemId, UmbracoNode source, ISession session)
   at Umbraco.Courier.Persistence.V6.NHibernate.Persisters.DocumentItem.RetrieveItem(ItemIdentifier itemId)
   at Umbraco.Courier.Core.ItemCrud`1.RetrieveItem[T1](ItemIdentifier itemId)
   at Umbraco.Courier.Core.ItemCrudProvider.RetrieveItem[T](ItemIdentifier itemId)
   --- End of inner exception stack trace ---
   at Umbraco.Courier.Core.ItemCrudProvider.RetrieveItem[T](ItemIdentifier itemId)
   at Umbraco.Courier.ItemProviders.ContentItemProvider`2.PerformHandlePack(ItemIdentifier id)
   at Umbraco.Courier.ItemProviders.DocumentItemProvider.PerformHandlePack(ItemIdentifier id)
   at Umbraco.Courier.Core.GenericItemProvider`1.HandlePack(ItemIdentifier id)
   at Umbraco.Courier.Core.ItemProvider.Package(ItemIdentifier id)
   at Umbraco.Courier.RepositoryProviders.Local.Package(ItemIdentifier itemId)
   at Umbraco.Courier.RepositoryProviders.Local.Hash(ItemIdentifier itemId)
   at Umbraco.Courier.RepositoryProviders.Webservices.Repository.GetHashes(String sessionKey, ItemIdentifier[] itemIds)
   --- End of inner exception stack trace ---
   at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.EndInvoke(IAsyncResult asyncResult)
   at Umbraco.Courier.RepositoryProviders.WebServiceProvider.RepositoryWebservice.EndGetHashes(IAsyncResult asyncResult)
   at Umbraco.Courier.RepositoryProviders.CourierWebserviceRepositoryProvider.GetHashes(ItemIdentifier[] itemIds)
   at Umbraco.Courier.Core.Packaging.RevisionPackaging.GetTargetHashes(IPackagingTarget2 target, IEnumerable`1 ids)
   at Umbraco.Courier.Core.Packaging.RevisionPackaging.PackageBatch()
   at Umbraco.Courier.Core.Packaging.RevisionPackaging.Package()
   at Umbraco.Courier.Core.Tasks.PackagingTask.Run()
   at Umbraco.Courier.Core.BackgroundTaskRunner`1.ConsumeTaskInternal(T task)