When planning to deploy a 4D application, first check that the 4D version used to build the application supports your clients' operating systems (OS). For example, if you built a merged app with v18 R4, it is not recommended to deploy that application to macOS less than Mojave (10.14), like High Sierra (10.13). You can check for minimum system requirements on the product dowload page at us.4d.com. Note that for later version releases, by extension, you can expect that the OS support will not move backwards from earlier versions. Thus, you can expect that v18 R5 will not support any macOS before 10.14 as well.