Patrick Zaw – Blog

public SPListItemVersion GetLatestMajorVersion(SPListItem listItem)
        {
            SPListItemVersion latestMajorSourceFileVersion = null;

            foreach (SPListItemVersion sourceListItemVersion in listItem.Versions)
            {
                Version thisVersion = new Version(sourceListItemVersion.VersionLabel);

                if (thisVersion.Minor != 0)
                {
                    continue;
                }
                else
                {
                    if (latestMajorSourceFileVersion != null)
                    {
                        Version v = new Version(latestMajorSourceFileVersion.VersionLabel);
                        if (thisVersion.Major > v.Major)
                        {
                            latestMajorSourceFileVersion = sourceListItemVersion;
                        }
                    }
                    else
                    {
                        latestMajorSourceFileVersion = sourceListItemVersion;
                    }
                }
            }

            return latestMajorSourceFileVersion;
        }