[Bug]: Merged fix for #36192 Fails [Fix reminder timezone drift for all-day events #36192}

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

The merged fix for timezone drift for all day event reminders described in bug #36192 is not working properly in NC26.0.4. See https://github.com/nextcloud/server/pull/36192

At least one other user on the nextcloud forum is describing the same. See https://help.nextcloud.com/t/calendar-timezone-bug-36192/167212

Calendar is still using server time (generally UTC) instead of calendar time zone.

Steps to reproduce

1. create all day event on calendar
2. schedule email reminder
3. save event with reminders

Expected behavior

Reminder should arrive as scheduled in users selected time zone. instead reminder is arriving based on server time zone, which is generally UTC. In other words, if reminder should arrive at 9am New York City time (America/NewYork) the day before an all day event, it arrives at 5am New York City time (America/NewYork), because New York is 4 hours later than UTC.

Installation method

Community Web installer on a VPS or web space

Nextcloud Server version

26

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.1

Web server

Apache (supported)

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

i dont know how to do this

List of activated Apps

not sure how to do this

Nextcloud Signing status

not sure how to do this

Nextcloud Logs

not sure how to do this

Additional info

none

Start by reviewing the linked fix in pull request #36192, then reproduce the all-day event reminder steps described in this issue. Compare the scheduled and delivered times across a non-UTC calendar timezone; done means reminders arrive at the selected timezone rather than server time.