Current Limitations
JIRA Client is not a full substitute for JIRA web interface. It addresses most of use cases and we're working on supporting every feature that you request. Yet the current version has limited functionality.
Performance
Currently, JIRA Client can download and handle effectively up to 10,000 issues.
If you have more issues in JIRA, that's ok unless you work with each and every issue. Use queries to download issues only for your project, or only open issues, or use whatever filter that defines which issues you are working with.
If you need to work with more issues anyway, give it a try. JIRA Client won't stop on issue number 10,001, though it may seem slower and require more memory. Meanwhile, we'll be working hard to push the limit into the sky.
Functional Limitations
Following is the list of standard JIRA features that are not supported by JIRA Client (as of version 1.2 Beta 1).
- Custom field types not fully supported: multiple version picker, multiple group picker, multiple user picker;
- Comment visibility (all comments will be visible to "all" group);
- Time tracking;
- Context-based values in custom fields (when available options are dependent on project and/or issue type);
- Issue deletion is not supported (no action to delete an issue; if an issue that has been downloaded is deleted on server, it will remain in JIRA Client);
- Grouping versions as "Released/Unreleased" and "Archived/Unarchived" - supported only in distributions;
- List of users is not automatically downloaded (users "table" is populated based on issues downloaded);
- Free text search by relevancy (JIRA Client will search for exact words typed);
- Clone issue;
- History of changes.
I Need an Unsupported Feature
When you find out that you can't do something with JIRA Client, you can always press F9 and JIRA Client will take you to the issue's web page in JIRA. You have to be online, of course.
You are also welcome to request a feature that you need.

