This document provides general recommendations for FortiOS Software deployments to ensure overall stability for customers. It is regularly updated on a quarterly basis.

When considering the recommended release for FortiOS, it is essential to evaluate several factors that influence the choice of version. The recommendations can vary based on specific use cases, hardware compatibility, and the stability of the software. Below are detailed steps to guide you in selecting the most suitable FortiOS version.

1. Understanding Version Types

Fortinet classifies its software releases into two primary categories: Feature Releases and Mature Releases.

• Feature Releases (e.g., 7.0.x) introduce new functionalities but may also contain undiscovered bugs due to less extensive testing.
• Mature Releases (e.g., 7.2.x, 7.4.x) focus on stability and bug fixes, making them more suitable for production environments.

It is advisable to choose a Mature Release for critical applications where stability is paramount.

2. Current Recommended Versions

As of now, Fortinet has not explicitly listed FortiOS versions 7.2 and 7.4 as recommended in their latest updates, despite these versions addressing vulnerabilities that affect earlier versions like 7.0.x. Users are encouraged to monitor the official documentation regularly since this list is updated quarterly.

Key Considerations:

• If your current version is nearing its End of Engineering Support (EOES), which for 7.0.x is March 30, 2024, transitioning to a newer version such as 7.2 or 7.4 may be necessary.
• Check if your hardware supports the desired version; some models may have limitations regarding which versions they can run effectively.

3. Evaluating Vulnerabilities and Patches

Recent vulnerabilities have been reported affecting older versions like 7.0.x without available patches, while newer versions provide fixes or are not affected at all:

• For instance, vulnerabilities disclosed in December 2023 and February 2024 had no patches available for version 7.0.x but were addressed in later releases.

This situation underscores the importance of migrating to a fixed release that offers security against known vulnerabilities.

4. Release Notes and Support Terms

Before upgrading:

• Review the release notes associated with each FortiOS version carefully to identify any potential issues or changes that could impact your environment.
• Be aware of support timelines: After EOES, only critical issues will receive maintenance builds.

5. Upgrade Path Considerations

Ensure that you follow the correct upgrade path when moving from one version to another:

• Direct upgrades may not always be possible; sometimes intermediate steps are required.

Consulting Fortinet’s documentation on upgrade paths will help ensure a smooth transition between versions.

Conclusion

In summary, while there isn’t a universally recommended version due to varying user needs and hardware configurations, it is prudent to consider upgrading from older versions like 7.0.x to more stable releases such as 7.2 or 7.4—especially given recent vulnerabilities and support timelines.

---

Authoritative Sources Used in Answering this Question

Fortinet Knowledge Base - This source provides comprehensive details about FortiOS releases, including their classifications and support timelines.

FortiGuard Labs - Offers insights into vulnerabilities associated with different FortiOS versions along with patch availability information.

Fortinet Community Forums - A platform where users discuss experiences with various FortiOS releases and share insights regarding best practices for upgrades and migrations.