Good news! Worklogs - Time Tracking and Reports team have just released a new version, and since you use Jira Server you can decide to upgrade at any time! All that is needed is a click of a button in the Apps management screen on your instance!
New features:
Support for sprints in Worklogs:
After selecting a project you can now select a sprint from a new select. After choosing a sprint the date will change automatically to start and end date of the sprint. Only issues included in this sprint will be shown in report.
Support for sprints in Worklogs Gadget:
In gadget configuration after selecting a project you can now choose a sprint and date range “this sprint“. Only issues included in this sprint will be shown in gadget.
Improvements
Renamed “Work time“ tooltip to Log time for consistency