How does the user Timezone is updated with winter/summer clock changes?

I'm running SugarCRM Community Edition (6.5.13) on linux server (centos) and it works great! 

one thing i don't understand, 

if each user has its own timezone, selected in it's user profile (advanced tab), for example "Asia/Jerusalem +2",

then what happens when the daylight savings time, changes on winter or summer (changes from +2 to +3 and then back to +2)?

does that mean the administrator has to manually, change the timezone of all user back and forward twice a year?

because if the user timezone stays as is, when the daylight savings change, then the user will see wrong datetime values presented throughout the system....

i need to implement an automatic solution for this.

since i'm familier with sugarcrm code, i thought of setting all users to UTC Timezone and change some code,

so all datetime presented in the system, will take the timezone of the machine the current browser runs on (win10/mac/android) and this way the timezone will always be currected, but it looks complicated....

any ideas how to keep timezone in sync on summer/winter daylight savings?

thanks!