Hello FlexMickeyBob;

Hati has provided you with the correct answer. Here are a few more details, so you can find this by yourself fir any Siemens automation equipment.

First, look at the screenshot below, taken from this product information  on Step 7 v5.7 (from the Industry Mall, Soemens'electronic catalog):

https://mall.industry.siemens.com/mall/en/CA/Catalog/Product/?mlfb=6ES7810-4CC12-0YA5&SiepCountryCode=CA

Notice the line showing that Step 7 v5.7 is designated PM300, which means it is an active product.

If ever it goes to PM400 status  phased-out, it will remain available for at least 10 more years, until is is canceled (only available as spare part replacement) then  eventually, discontinued as PM500 (no longer available).

This is discussed in this Siemens article on the Product Life Cycle of Siemens HMI panel; the same designations apply to all Siemens automation products and softwares:

https://support.industry.siemens.com/cs/de/en/view/91688124

You can reassure your client that he has at least 10 more years of availability for Step 7 v5.x, probably something more like 15. 

Hope this helps,

Daniel Chartier 

Hello FlexMickeyBpb;

I cannot vouch for Siemens long-time maintaining of external software packages.

The Control interface is a relatively new product, based on Microsoft.Net, and it will have to evolve as these basis softwares evolve too (anyone remember all those products developped with VB6?). For example, at present, the command interface only supports 32-bit applications. When it is eventually ported to 54-bit, no one can say at this time how it will transform, or how it will continue to support older implementations.

One example of such issues, from the Step 7 v.7 readme file:

"Restricted use of scripts in the STEP 7 command interface on Windows 10

Due to thread synchronization problems when automatically saving STEP 7 user data, Visual Basic script applications can experience sporadic crashes (possibly with data loss). Therefore, the command interface is currently only partially suitable for such applications. Unpredictable errors can occur, especially with nested loop operations. It is highly recommended that you avoid such use cases and use Visual Basic scripts only with care and caution."

file:///C:/Users/danie/OneDrive/Documents/Siemens%20forum/STEP_7_V5_7_ReadMe.pdf

Hope this hels,

Daniel Chartier