Support for non-Gregorian calendar systems (Persian, Hebrew, etc.)

[iJahangard]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs), in the README and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the request may get dismissed otherwise.
• This issue contains only one feature request.

Which apps should have this feature?

No response

Feature description

Besides all the world uses georgian date system my country and some others uses their own date systems like Persian date, hijri date and so on(I don't know other dates)

Why do you want this feature?

Having support of Persian date in common apps that all people use them a lot were the one feature that I always wanted, Georgian date is not something that I can plan using it or schedule my tasks, so always have to convert dates, sadly!
Having this feature allow me to have a good understanding of my timeline and also saves a lot of time in apps like messages, dialer, calendar, and etc .

Additional information

Some GitHub projects that might be useful
https://github.com/MohammadSadeghMehrafzoon/ConvertDateAndTimeToPersian
https://github.com/FatulM/shamsi_date
https://github.com/AmirSinaRZ/PersianCalendar

https://github.com/topics/jalali?l=kotlin

[naveensingh]

Which apps should have this feature?
No response

It would be great if you could fill out that section.

[alr86]

Besides all the world uses georgian date system my country and some others uses their own date systems like Persian date, hijri date and so on(I don't know other dates)

• Chinese Calendar
• Coptic Calendar
• Ethiopic Calendar
• Gregorian Calendar
• Hebrew Calendar
• Indian Calendar
• Islamic Calendar
• Buddhist Calendar
• Japanese Calendar
• Taiwan Calendar
• ...

[iJahangard]

Which apps should have this feature?

Messages, calendar, phone, contacts, file manager & recorder

All of these have parts that might need a date converter but the one i need more is messages app

[afshin-ir]

Hello,

Here is a simple Kotlin utility class for converting epoch timestamps to Jalali date strings.

This can be integrated into the call log display to support Jalali dates as requested

https://paste.ubuntu.com/p/HvphmFS4df/

[HaleyHalcyon]

• Japanese Calendar

As a Japanese person myself, I can pitch in with insight.

In the current day, all business in Japan is carried out in the Gregorian calendar, except that the years are also numbered in the era name system (元号). This is also sometimes translated as the “regnal name”. We use the era name for official purposes, but civilians either use both names, or prefer the Gregorian year number.

One oddity is that “year 1” starts from the middle of the year, and has a special name in Japanese (元年 instead of the expected 1年). Therefore, the year 2019 was called “Heisei 31 / 平成31年” until April 30, then “Reiwa 1 / 令和元年” from May 1. (And because this system predates computing, it starts counting at 1 😭)

As of 2025/09/23, here are the gengō / era names / regnal names in common use:

• 明治 Meiji: 1868/10/23 – 1912/07/29
• 大正 Taishō: 1912/07/30 – 1926/12/25 01:24:59 (Wikipedia says it ended exactly on Emperor Taishō’s death on 12/25. Yes, mid-day year name changes. That’s the level of cursedness we’re at.)
• 昭和 Shōwa: 1926/12/25 01:25:00 – 1989/01/07
• 平成 Heisei: 1989/01/08 – 2019/04/30
• 令和 Reiwa: 2019/05/01 – present (Will end some day in the future unannounced when the current Emperor dies [unless he decides to abdicate ahead of time like the former Emperor did]. We—or the date-time library implementers—have to scramble to implement that)

Each era name since Meiji can be abbreviated as a single Latin-script letter (M, T, S, H, R). Of course, this practical point is not the only consideration when choosing a new era name, but when the era name after Shōwa was down to 3 candidates, the other proposed names Shūbun 修文 and Seika 正化 were rejected for Heisei, the only candidate that did not start with an “S” for Shōwa. This is not an official criterion, but it’s a precedent that Reiwa followed.

There is also the lunisolar calendar based on the Chinese calendar, but it’s practically no longer used. Safe to ignore, IMO.

[herotux]

I’d like to contribute an implementation for Persian/Jalali calendar support, initially targeting Messages and Calendar, with the date conversion/formatting designed so it can be reused by other Fossify apps.

I already have a working prototype in my fork of Fossify Messages, including locale-aware formatting and tests. Before opening a PR, I’d like to confirm the preferred architecture and contribution path for #306.

For the Persian locale, the intended display is e.g. ۳۰ مرداد ۱۴۰۵; for English locale, 30 mor 1405 (Latin digits and a Latin month abbreviation).

Would the maintainers prefer this functionality to live in Fossify Commons as a shared date/calendar utility, or initially in Fossify Calendar and then be extracted/shared?

I’m happy to adapt the implementation to the project’s preferred design and contribution requirements.