Author's comment since this blog was first published: It is generally recommended to choose the most recent version of Zowe unless there are specific reasons to use a prior version. Note: it is best to confirm with the authors of any applications if they support the most current version of a runtime environment. There can be a lag between the release of a new runtime version and an application being tested on that version. 

So, you’re interested in Zowe, but you are not sure how to get started. How about ordering the code – at no charge - to try out? Or maybe you need Zowe as a pre-requisite for another IBM product and you want an easy, secure way to obtain it? Or maybe you are developing an in-house Zowe application and want defect support for Zowe technology?  In this article we will share the options for obtaining Zowe code, discuss a few of the important Zowe use cases and advise you when Zowe Support from IBM is entitled, and when you may want to purchase defect support.

First familiarize yourself with the technology.
Zowe is made up of four (or more) software components that can be used individually or integrated together in different combinations. Two server components (the Application Framework (aka Desktop or Web UI) and the API Mediation Layer) run-on z/OS. The other two components (Zowe Explorer and CLI) run on client environments (laptop/desktop or cloud). There is a wealth of documentation and videos available on zowe.org . Be sure to select the right version and release level you are using in the upper right corner of the documentation. Documentation contents can vary by version and release as new capabilities are introduced.  IBM products that use Zowe components are described here.

You have options on how to obtain the code - open community, vendor or combo.
IBM offers IBM Z Distribution for Zowe 2.0 and 3.0. (5698-ZWG and 5698-ZWH). The z/OS components of Zowe are available via Shopz. There is a new, streamlined Shopz ordering process for open source on z/OS, check out this article.

A few words about Zowe use cases - standalone or with vendor products. 
Zowe can be used in two ways. First, Zowe can be used “standalone” – meaning without any other IBM (or 3^rd party) products other than the z/OS operating system and the REST APIs inherent in z/OS provided by the z/OS Management Facility (z/OSMF).  Zowe provides out-of-the-box capabilities such as basic file and data set editing, view and manipulation of JES spool files, job submissions, console commands, web browser based 3270 or VT emulation, basic z/OS REST API management, etc. (All of the capabilities are managed by z/OS security policies.) For some consumers, Zowe standalone is enough for them. It delivers productivity gains and IT staff enjoy using the familiar interfaces of REST APIs, CLI, browsers and VS Code extension.  

Second, Zowe is an extensible software framework, and some IBM and 3^rd party products provide integrations with Zowe using one or more of the Zowe components. For example, products that have REST APIs can import those API definitions into the API Mediation layer. Products can provide extensions to the Zowe CLI to allow scriptable text commands to be used with their particular product REST APIs. Other products have adopted the Zowe Application Framework for either their singular user interface or as an optional user interface.

This brings up an important point, some products require a Zowe component to function (like those using the Application Framework as the only available user interface) and other products optionally use one or more Zowe components. In these cases, Zowe code is not required but it enhances some aspect of the product. Big hint - the IBM Zowe Support Page tells you which IBM products require Zowe and for which it is optional. 

When is Zowe Required or Optional with IBM Products? 
In most cases, IBM products should document – either in the announcement letter, documentation, or program directory – when Zowe technology is required, which Zowe component is required, when is Zowe optional and how to get the product's Zowe integration code. Often the Zowe integration code (REST API, CLI extension, etc.) is included in the IBM product deliverables but may also be hosted on one of the public code repositories mentioned above like npmjs or VS Code Marketplace.  

Two tables are provided and maintained (along with some additional information) on which IBM products require Zowe components and when Zowe components are optional. The following information is example but please use the IBM Zowe Support Page for the most up-to-date information – watch for any updates on the Support page. 

Examples For Which IBM Products is Zowe Required. 

[1] There can be exception cases if/when emergency fixes are needed in the process of providing support to a consumer of Zowe.

[2] Portable SoftWare Instance (PSWI) is a newer software package format for z/OS.