Modern versions (Flexi 12, 19, 22) have moved to a $50–$150/month subscription model. Many users hate recurring fees and prefer the "own it forever" model of version 10.5.1.
If you absolutely need FlexiSIGN Pro 10.5.1 Build 1806 for legacy equipment: flexisign pro 105 1 build 1806 loader exclusive
Finding a clean, functioning version of Build 1806 is increasingly difficult due to its age and the prevalence of infected "exclusive" loaders. Ebay/Third-Party Modern versions (Flexi 12, 19, 22) have moved