IGEL OS Base System 12.4 Current: Upgrading from IGEL OS 11 to IGEL OS 12 PDF Download PDF Download page Upgrading from IGEL OS 11 to IGEL OS 12. Current page All pages Upgrading from IGEL OS 11 to IGEL OS 12 For instructions on upgrading endpoint devices from IGEL OS 11.09 to IGEL OS 12 via the Universal Management Suite (UMS), see Upgrading (Migration) from IGEL OS 11 to IGEL OS 12. ×