IBM i Access Client Solutions provides a Java based, platform-independent interface that runs on most operating systems that support Java, including Linux, Mac, and Windows™. The latest version of IBM i Access Client Solutions is available to customers with an IBM i software maintenance contract. I'm not aware of an 'iSeries Access for Mac' product version. I think there is one for Linux and there might be some potential there depending on what OS your Mac is running (I'd be surprised, but 'nix stuff can sometimes surprise pleasantly.) However, I'm pretty sure some iSeries Access functions can be done on a Mac by various other products.
Try for free today!
We use both the old verision (6.1) and the newer java based version on windows 10. Our programmers prefer the java based, but I left all of our desktops on 6.1 and they work just fine after the systems were upgrade to win 10.
IBM will not support if you have any issues while running the old version, but that does not mean it will not work with win 10. The only thing I ran into was using PDT for printers, it did not seem to work for us after the upgrade, but it was only a handful of PCs that we used PDT settings on a printer, so no big deal. We run Windows 10 and Server 2008/2012, and use the v7r1 client every day without a problem, both 32-bit and 64-bit, depending on the client O/S.
We have Excel/VBA macro-enabled spreadsheets, VBScripts, and PowerShell scripts as part of our daily operations, including server side scheduled tasks. I use multiple sessions of the green screen every day. My boss uses the 'import data to Excel' function weekly.
What I cannot tell you is anything about the AS400 system itself, it is a hosted service and we just connect to it. Yes IBM i ACS is the new java based Client Access replacement product that is supported on Windows 10. But to use that client on Windows 10 may require the upgrade of the OS from 5.3 to 5.4 but you probably should go to 6.1 and then to 7.1 There are many advantages in v6.1 and even more in v7.1 The jump to v6.1/v7.1 requires a conversion of objects. There is a tool/report you should use first to see any problem areas. If you have the room on the system, you may want to create another LPAR, restore your current system to it and test the upgrade. Again, since you are so far back, you may want to get some assistance.