As of OpenUI5 1.6 there is a close coupling of OpenUI5 core/runtime and OpenUI5 tools: It is required that within a running system both have the same version, that is, have the same major and minor version.
For example, OpenUI5 core/runtime 1.x.1 works together with OpenUI5 tools 1.x.2, but not with OpenUI5 tools 1.y. For a future release it is planned to have a more loose coupling here with regards to the minor and micro version.
As of OpenUI5 1.6 we can only support customers who follow this rule in their system landscapes.
OpenUI5 uses a 3-digit version identifier, for example 1.26.4. These digits have the following meaning:
The version number for each new OpenUI5 release contains a major and minor version number. The patch version number is only used to identify patches within a release.
You can switch to a different version as described in Variant for Bootstrapping from Content Delivery Network.
Check the available versions with respective maintenance status at https://sdk.openui5.org/versionoverview.html.