File not Found after upgrade from 2.7.0 to 2.19.0 (2.8.0)

[Toprakete]

Hi, I want to list files of a folder. I did this with:

public boolean requestFileList() {
    ReadFolderRemoteOperation refreshOperation;
    // prepare client
    prepare();
    // request
    if (TextUtils.isEmpty(mFolder)) {
        refreshOperation = new ReadFolderRemoteOperation(FileUtils.PATH_SEPARATOR);
    } else {
        refreshOperation = new ReadFolderRemoteOperation(FileUtils.PATH_SEPARATOR + mFolder);
    }

    refreshOperation.execute(mClient, new OnRemoteOperationListener() {
        @Override
        public void onRemoteOperationFinish(RemoteOperation operation, RemoteOperationResult result) {
            if (!result.isSuccess()) {
                mProjectHandlerDelegate.projectDataDownloadFailed(result.getHttpCode(), result.getLogMessage());
            } else {
                // create db filelist
                processFileList ((ReadFolderRemoteOperation)operation, result);
            }
        }
    }, mHandler);
}

private void prepare()
{
    // already inited?
    if (mClient != null) return;
    // create client
    Uri serverUri = Uri.parse(mServer);
    mClient = OwnCloudClientFactory.createOwnCloudClient(serverUri, getContext(), true);
    mClient.setCredentials(
            OwnCloudCredentialsFactory.newBasicCredentials(
                    mLogin,
                    mPassword
            )
    );
}

This worked fine, until I upgraded to 2.19.0 (it happens already in 2.8.0). The result is then 404, File not Found As I saw the the query url has a null where the userid should be. How can I fix this? Thx and br Klaus