App: beQUIET
Developer: Jiulong Zhao
Genres: Bildung, Produktivität

"It is a must-have app for all Macs that will be used in school, library, and public places!"

As long as beQUIET is running, your Mac's internal speakers are muted. Meanwhile, you may still listen through your headphone jack. 
Simpto says, beQUIET only mutes your internal speakers in any condition. 

beQUIET is designed for journalists, teachers, students, and other Macbook users who want to hear the sound but do not want to disturb others, such as in meetings, classrooms, courts, lectures, and theaters. 

Benefiting from your Mac's high-end hardware design, beQUIET guarantees that your speakers stay quiet and your headphones work no matter if you plug or unplug your headphones!

This App is developed due to the request of a teacher who needed his computer lab to be quiet, but still, let the students enjoy the sound with their headphones.  

features v1.66 
- Check the internal speaker's status and mute them in real time; 
- Saves and sets the speaker's volume automatically before and after running; 
- Easy-to-use interface; 
- Animated menu icon; 
- No need for any additional hardware; 
- Headphones' mute status and volume can be freely adjusted; 
- Feature requests are welcome and lifetime free upgrades; 

v1.66 -> v1.68 
- simple password function added for teachers and parents;

v1.68 -> v2.15
- add an option to hide the app's desktop interface
- change the exit alert's default selection
- status menu bar icons modified for better flashing looking
- add "feature request" menu
- add "more by dragonBTV" menu

v2.15 -> v2.28
- add an option to hide the dock icon
- add an option to start at login
- add an option to bypass password
- add an option to remember the password
- add an option to bypass the exit alert
- more detailed technical support email templet 
- more detailed feature request email templet 
- updated more by the dragonBTV panel

v2.28 -> v2.40 
  important upgrade according to the user's feature request: 
-add a Fully Customizable Global Hotkey to invoke mute internal speaker or not. (hotkey preset to command + control + shift + h) 
- partly rewrite code for better performance 
- more by dragonBTV panel updated

v2.40 -> v2.51
  important upgrade according to the user's feature request: 
- add the option of Mute Mac's Startup Melody
- add the option of stopping the flashing status menu bar icon
- add option auto re-mute internal speaker after Mac's sleep
- add Show Tips to the help menu
- icon color changed from red glass to silver metal
- Sandbox-compatible email technical support 
- Sandbox-compatible feature request support 
- Sandbox-compatible "more by dragonBTV" menu and panel
- Sandboxed OS 10.6 -10.8 compatible version

 v2.51 -> v2.58
add option according to user's feedback
- add an option to bypass password resetting during the app's start

v2.58 -> v2.59
- add more diagnose while users are using other output devices e.g. Bluetooth earphones and make the popup information more user-friendly
- global hotkey alert text modified
- more by dragonBTV updated

v2.59 -> v3.00
- fully re-coded for macOS Sierra 10.12 
- updated to macOS Sierra 10.12 and still compatible with OS10.7 and above
- fix the display issue on the hotkey setup menu under macOS 10.12
- hide dock icon option updated for instant switching without restarting the app
- the user should key in the password while switching to hotkey mode
- user notification added on mute mode change
- dark menu mode supported 
- status menu icons were refined
- icon color changed
- on desktop panel redesigned
- change the color of all popup alerts and panels to white
- tip added for auto open at login (autostart​)
- startup tip updated
- more by dragonBTV updated

v3.00 -> v3.01
- app size dramatically reduced
- menu re-arranged for simplification
- more by dragonBTV simplified
- performance improvements for macOS 10.13 High Sierra

v3.01 -> v3.05 -> v3.10 -> v3.21 see read me for details because of the words limitation of the description

Release notes:
v3.10 - v3.21
- user notification updated, all deprecated code rewritten
- deprecated code updated for Keychain wrapper
- code fully rewritten, display interface modified
- bug fixed, display image not matching the mute state when flashing
- bug fixed: password popup window always displays top most now
- More by dragonBTV menu updated