21CS VSEn
New Name, Full Compatibility
VSEn v6.3 key features and future direction reflect 21CS’s investment in the VSE ecosystem
Overview
Future of VSEn
Technical Specs

INVESTING IN THE FUTURE OF VSEn
Our first version of the VSE operating system (OS) enters the market under the name: VSEn V6.3. VSEn is designed to offer non-disruptive compatibility with previous versions of IBM z/VSE (which serves as the basis for VSEn V6.3), leveraging the source code license agreement the company completed on June 1, 2021. VSEn V6.3 also addresses fixes and features that have been applied to IBM z/VSE 6.2 through March 2022, along with the newest releases of the TCP/IP stacks and installation enhancements.
Support for new generations of IBM Z hardware
Investing in the Future of VSEn
We ‘re working with active VSE vendors interested in investing in and strengthening the VSEn ecosystem in key areas like security, storage, resiliency, observability, and connectivity. Some of these VSE vendors include:
- Adaptigent
- B.O.S. Software
- Barnard Systems Inc.
- Broadcom Mainframe Software
- C/Trek
- Cincom
- CSI International
- Cyber Gent
- Erdani
- FIS
- H&M Systems Software
- Lattwein GmbH
- Log-on
- MacKinney Systems, Inc.
- Phoenix Sofware
- Precisely
- Q Group
- QMSI
- Rocket Softtware/ASG
- SDS
- Thigpen
- Treehouse Software
- Unicom Global & Macro4
- Velocity Software
- XPS Software

Join Our Team
Continuous innovation also means investing in the right talent and expertise. 21CS has developed a sustainable team of seasoned VSE experts who work closely with new, innovative developers. Together, the team is prepared to effectively maintain and improve upon the OS and middleware stack well into the future.
If you are looking to join our team of VSEnexperts, check out job opportunities..
Is VSEn right for you? Let us know.
News Archive
21CS Brings VSEn 6.3 to the New IBM z16 Single Frame and Rack Mount Models
We are excited to collaborate with IBM on its new IBM z16 single frame and rack mount options that became available in May.
IBM z16: The Ideal Platform for VSE Business Needs
The recent IBM z16 unveiling, coupled with 21st Century Software’s announcement of VSEn 6.3 in March, provides VSE users with all the more reason to confidently move ahead with VSEn and IBM zSystems servers.
21st Century Software Announces VSEn V6.3
21st Century Software today announced its first version of the VSE operating system (OS)—which enters the market under the name: VSEn V6.3 with planned availability for May 17, 2022.
“IBM is pleased that 21CS has chosen to license the source code for the z/VSE operating system. We are working closely with the team to enable continued value to our customers.”
—Barry Baker, IBM VP, Product Management, IBM Z and LinuxONE
Technical Specifications
Middleware stack names have also changed, but executables (commands, jobs, APIs) have not have not been renamed to maintain compatibility for customers coming from IBM z/VSE. Here’s a look at the new names for the components we are delivering across the stack:
21CS Product Name
VSEn
OLTP for VSEn for OLTP
VCDD for VSEn for VCDD
HLASM for VSEn HLASM
IDRP for VSEn for IDRP
ICKDSF for VSEn for ICKDSF
21CSW IPv6/VSE
HDB for VSEn for HDB
Encryption Facility for VSEn
Newly Released Products
MQ for VSEn
Newly Released Products
GPSP for VSEn
GPSP-IVU for VSEn
GPSP-IMD for VSEn
GPSP-PGF for VSEn
Newly Released Products
SCRDEF for VSEn
C for VSEn
Newly Released Products
Current GA Release
6.3
2.3
4.3
1.6
3.6
1.18
1.4
2.31
1.13
1.3
Q3 2023
3.1
Q2 2023
3.3
1.2
2.2
2.2
Q1 2023
1.13
1.2
Q4 2022
1.4
3.5
1.2
1.2
1.2
7.6
7.6
1.6
1.3
1.4
IBM Product Name
z/VSE
CICS TS
ACF/VTAM
EREP
DL/I
WebSphere MQ
GDDM
GDDM-IVU
GDDM-IMD
GDDM-PGF
SDF II
DITTO
DFSORT
DB2 Server
DB2 Client
ACLR
Resources:
SUPPORT
+1 800-555-6845 | +1 610-971-9946
For VSE Support

We’re Listening
In the survey, you’ll have a chance to communicate particularly important VSE strengths, potential future needs, pressing issues and more. Your answers will help 21st Century Software guide future direction for VSEn —so be sure to make your voice heard.

21CS is a leader in the development of software solutions that are designed to create value across the business and IT spectrum.
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