added clarity about sql 2008 upgrade

Author: MashaMSFT

docs/database-engine/install-windows/upgrade-sql-server.md

@@ -16,7 +16,7 @@ monikerRange: ">=sql-server-2016||=sqlallproducts-allversions"
 # Upgrade SQL Server
 [!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md-winonly](../../includes/appliesto-ss-xxxx-xxxx-xxx-md-winonly.md)]
 
- You can upgrade instances of [!INCLUDE[ssKatmai](../../includes/sskatmai-md.md)], [!INCLUDE[ssKilimanjaro](../../includes/sskilimanjaro-md.md)], [!INCLUDE[ssSQL11](../../includes/sssql11-md.md)], [!INCLUDE[ssSQL14](../../includes/sssql14-md.md)], or [!INCLUDE[ss2016](../../includes/sssql15-md.md)], to [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)]. Before running [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Setup to upgrade to [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)], review the following articles about the upgrade process and the release notes.  
+ You can upgrade instances of [!INCLUDE[ssSQL11](../../includes/sssql11-md.md)], [!INCLUDE[ssSQL14](../../includes/sssql14-md.md)], or [!INCLUDE[ss2016](../../includes/sssql15-md.md)], directly to [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)]. For [!INCLUDE[ssKatmai](../../includes/sskatmai-md.md)], and [!INCLUDE[ssKilimanjaro](../../includes/sskilimanjaro-md.md)], you'll either need to do a side-by-side upgrade, or a migration, to move to SQL Server 2019 as there is no common overlap between a supported mainstream operating system. Before running [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Setup to upgrade to [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)], review the following articles about the upgrade process and the release notes.  
 
    - For information about upgrading from [!INCLUDE[ssVersion2005](../../includes/ssversion2005-md.md)], see [Are you upgrading from SQL Server 2005?](../../database-engine/install-windows/are-you-upgrading-from-sql-server-2005.md).  
    - [SQL Server 2016 Release Notes](../../sql-server/sql-server-2016-release-notes.md)