ZT vs Sirius
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ZT
Connect with incarcerated individuals through a comprehensive mobile service. Send letters, photos, make audio/video calls, and transfer funds. Offers entertainment options like puzzles and games to enrich communication.
- Send electronic letters and photos
- Make audio and video calls
- Transfer money to inmate accounts
- Add puzzles and games to letters
- Instant printing at correctional facilities
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ZT — крупнейший сервис для поддержания общения с заключенными и осужденными в России. Все услуги в одном приложении: от письма до видеовызова. Электронные письма Отправляйте текстовые письма, цветные или чёрно-белые фотографии через приложение. Моментальная печать в учреждении, проверка цензором от 1 до 3 дней. К письму можно добавить раскраски, японские кроссворды, судоку, оригами и шахматные задачи. Это поможет вашему близкому провести время с пользой. Аудио и видео вызовы Общайтесь голосом или по видео через мобильное приложение. Аудиовызовы в приложении дешевле сотовой связи до 48% в зависимости от региона. Видеовызовы в ZT доступны только в приложении. Денежные переводы Переводите деньги на личный счёт осужденного, чтобы он мог купить всё необходимое в магазине учреждения. Перевод доходит до учреждения за 1-3 рабочих дня. Скачивайте приложение ZT и поддерживайте связь с близким человеком!
Sirius
This app serves as a unified digital platform for residents and guests of a specific region. It consolidates essential services, including a digital profile, event calendar, exclusive bonuses, and news, all accessible from a mobile device. Users can stay informed about events, register for activities, and gain entry using a personal QR code.
- Digital resident and guest profile
- Event calendar and registration
- Personal QR code for entry and bonuses
- Exclusive partner discounts and promotions
- Unified digital space for regional services
- News and updates
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«Sirius» – educational environment» is a convenient mobile app that brings together all key services for residents and guests of the region. The digital resident and guest profile, event calendar, exclusive bonuses, and news — all in one place! Stay updated on the latest events, register for activities, and attend them using QR code. After registering in the project, a personal QR code is automatically generated in your account. This code is used for entry to events as well as for receiving bonuses from project partners. Project partners offer users special discounts, bonuses, and promotions. Just show your QR code or your «Sirius» Federal Territory resident and guest card to a partner to enjoy the benefits. «Sirius» – educational environment» is a unified digital space for residents and guests of the territory. Download the app and join in. Take full advantage of everything right from your mobile device!
Screenshots
Verdict
The clearest difference is rating: ZT at 4.6 against Sirius's 2.6. ZT also leads on ratings volume (303 vs 5) and iOS requirement (12.0 vs 15.0). Sirius's advantage is review sentiment (60% vs 18%) and update cadence (every 9 days vs every 3 weeks). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
ZT holds the better App Store score, 4.6 against 2.6. That said, the two scores are not equally well evidenced: ZT has 303 ratings behind it against 5, so its average is the more settled of the two. Written reviews complicate that: 18% of ZT's written reviews are positive against 60% of Sirius's, so the app with the better star average is not the one people write more warmly about.
ZT ships an update every 3 weeks, Sirius every 9 days. The most recent releases landed on November 13, 2026 and November 12, 2026 respectively.
| Parameter | ZT | Sirius |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (303 ratings) — better | 2.6 (5 ratings) |
| Positive reviews | 18.5% of reviews | 60.0% of reviews — better |
| Number of ratings | 303 — better | 5 |
| Update frequency | Every 3 weeks | Every 9 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 12.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 121 MB | 206 MB |
| Age rating | 4+ | 4+ |
| Developer | ZTK, OOO | AISA IT-SERVICE, AO |
Customer experience
ZT
Sirius
In-app purchases
ZT
No in-app purchases
Sirius
No in-app purchases
