There are multiple upgrade scenarios and “what ifs”, this is why it is not recommended for end user to do it; however it is theoretically possible to upgrade on your own – be sure you have full backup for SQL and your GP workstations (plus Server side software) to be able to roll back. GP has internal architecture, known as Microsoft Dexterity – this architecture drives upgrade process and deploys it own tools to do so. You should be familiar with such GP Dexterity features and terminologies as Dynamics.dic, Dynamics.set, Reports,dic, DEX_ROW_ID
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Microsoft Dynamics GP Great Plains Upgrade Service in Chicago – Alba Spectrum 
