Open Enterprise Server

Open Enterprise Server is a server operating system published by OpenText. It was first published by Novell in March 2005 to succeed their NetWare product.
Unlike NetWare, OES is a Linux distribution—specifically, one based on SUSE [Linux Enterprise Server]. The first major release of Open Enterprise Server could run either with a Linux kernel or Novell's NetWare kernel. Novell discontinued the NetWare kernel prior to the release of OES 2, but NetWare 6.5 SP7, and later SP8, can run as a paravirtualized guest inside the Xen hypervisor.

WWW Official Site

OES 1 and OES 2

Novell released OES 1, the first version of OES, on 25 March 2005. Since some users wanted backward compatibility with NetWare, Novell offered two installation options: OES-NetWare and OES-Linux. These are two different operating systems with different kernels and different userlands.
OES-NetWare is NetWare v6.5 equipped with NetWare Loadable Modules for various Novell services and open-source software.
OES-Linux is based on the SUSE Linux Enterprise Server with added NetWare services ported to the Linux kernel: e.g. the NetWare Core Protocol, Novell eDirectory, Novell Storage Services, and iPrint.
Novell released OES 2, the second version of OES, on 12 October 2007. It was the first SLES-Linux-kernel-only OES, but it retained the OES-NetWare operating system option, as NetWare 6.5 SP7 can run as a paravirtualized guest inside the Xen hypervisor. The SLES base of the OES 2 was later updated to SLES 10 SP1.
Features introduced in OES 2 include:

32-bit system or 64-bit system supporting 64 bit and 32 bit applications
Hardware virtualization
Dynamic Storage Technology, which provides Novell Shadow Volumes
Windows domain services
Apple Filing Protocol with Cross Protocol Locking AFP-NCP-Samba

OES 2015

OES 2015 was released on 31 August 2015, adding new features and improved performance.
OES 2015 SP1 was released on 14 June 2016 and was the first to be rebranded Micro Focus after Micro Focus purchased The Attachmate Group which included Novell.

OES 2018 & 2023

Micro Focus released OES 2018 in November 2017, with three service releases. All releases were all based on SLES 12 and its service packs.
While SUSE was sold by Micro Focus in 2018, SLES support and updates are included with an OES installation, provided at least one OES component is installed.
OES 2023 was released in October 2022, using a base of SLES 15 SP4. It includes a new Unified Management Console to supersede iManager for server management, TLS 1.3 support and was bundled with NetIQ eDirectory 9.2.7.
Breaking with previous convention, OES 23.4 was released in October 2023, and was rebranded to OpenText, after their purchase of Micro Focus earlier in the year. General support was extended to 3 years from the usual 2 years of previous releases.

Components

Automatic Client Upgrade automates the upgrade of Novell client software on existing workstations