CONDITIONS AND LIMITATIONS ON THE PROVISION OF SERVICES

2.1. Planned maintenance

For planned maintenance expected to cause a significant interruption, Koki gives advance notice in the application, on koki.vn or through other official channels.

We prioritise off-peak windows to limit the impact on users.

2.2. Unplanned interruptions

The service may be interrupted without advance notice in the following cases:

• Technical incidents, software defects or infrastructure failures
• Failures at infrastructure, server, network or third-party service providers
• Handling of security incidents, cyber attacks or service abuse
• Power or telecommunications outages
• Requirements of competent state authorities
• Force majeure events or events beyond Koki's reasonable control.

In these cases, Koki makes reasonable efforts to restore the service as soon as possible and notifies users where necessary.

2.3. Effect on the Premium term

A service interruption does not forfeit a Premium term that has been purchased. User entitlements in the event of a prolonged interruption are handled under the Service Provision, Service Termination and Refund Policy.

4.1. Age and legal capacity

Koki Flashcards is a learning application and may be used by people of a range of ages.

• Users must have the civil act capacity required to enter into transactions relating to the service themselves
• Minors transact in accordance with Vietnamese law on civil act capacity. Where the law requires a transaction to be consented to or carried out through a parent, guardian or legal representative, the user must ensure that condition is met before transacting
• Koki may request information or apply reasonable verification measures where there are grounds to believe the person transacting lacks the necessary rights or capacity
• For users who are children under Vietnamese law, personal data is processed under the Privacy Policy, including obtaining the consent of a parent, guardian or legal representative where the law requires it
• The application distributed through the Apple App Store and Google Play is also subject to each platform's age rating, shown on the relevant download page.

This section is consistent with Section 4 of the Terms of Service.

4.2. Account requirements

• Each user needs a Koki Flashcards account to store learning progress and receive Premium entitlements
• Premium entitlements are attached to the account, not to a device
• Users are responsible for the accuracy of their registration details and for keeping their account secure.

4.3. Restricted cases

Koki may refuse, suspend or terminate the service for accounts showing signs of breaching the Terms of Service, including payment fraud, abuse of promotional programmes, and unauthorised copying or distribution of Koki content.

5.1. Devices and operating systems

To use the application, users need a mobile device that meets the minimum requirements published on the application pages of the Apple App Store and Google Play.

Those minimum requirements are published by Koki on each platform and may change as the application is upgraded. The exact version currently in force is always shown on the relevant download page.

Devices running an operating system older than the minimum requirement may be unable to install the latest version, or unable to use certain features.

The koki.vn website works on recent versions of modern browsers (Chrome, Safari, Edge, Firefox) on both desktop and mobile.

5.2. Internet connection

Users need an Internet connection to register, sign in, download content, sync learning progress, pay, and use any feature processed on our servers.

Some downloaded content can be studied offline; offline progress is synchronised once the device reconnects to the Internet.

Mobile data or Internet charges are paid by the user to their own telecommunications provider.

5.3. Other conditions

• The device must have enough storage for the application and downloaded content
• Some features require the user to grant permissions (for example, microphone access for pronunciation practice, notifications for study reminders). Declining a permission disables the corresponding feature but does not affect the rest of the service
• Devices with a modified operating system (jailbroken or rooted) may run the application unreliably and fall outside Koki's technical support scope.

6.1. Scope of use

Users are granted a personal, non-commercial, non-exclusive and non-transferable right to use the service.

The service may not be used for commercial teaching, redistribution, resale or exploitation of Koki content for third parties, except under a written agreement with Koki.

6.2. Account limits

• Premium entitlements are attached to one account; the user may sign in to that account on their own personal devices
• Koki may apply reasonable technical measures to prevent account sharing among multiple people
• Each redemption code may be used once, for one account, and has an activation deadline stated in the email containing the code.

6.3. Technical limits on features that rely on third-party services

Some features carry a per-use operating cost (for example, pronunciation recognition and scoring, and features that use artificial intelligence) and may be subject to a daily or periodic usage allowance.

The allowance in force is shown in the application at the time of use. Koki may adjust it to keep the system stable and to prevent abuse; any adjustment must not remove the core entitlements a user has paid for.

6.4. Anti-abuse measures

Koki may limit access frequency and the number of requests sent to our servers, or suspend accounts engaged in automation, scanning, exploitation of vulnerabilities, or conduct that affects the system and other users.