For how often new versions now arrive, and what each kind of release means for an upgrade plan, see F5's monthly release cadence.

Ask when "BIG-IP" and "TMOS" became two different words and you get a precise answer: 7 September 2004, with the release of version 9.0. Before that, the hardware and the software were both just called BIG-IP (or the BIG-IP Controller), running on a base. Version 9.0 moved system management to Linux, introduced the Traffic Management Microkernel (TMM) to talk directly to the networking hardware, and from that point the hardware became the "BIG-IP platform" and the software became TMOS, the Traffic Management Operating System.

Slide through the rest below. Each stop shows the BIG-IP software version of that era and the operating system underneath it, from the BSD beginnings, through the long TMOS line, to F5OS and the VELOS and rSeries platforms that run BIG-IP as a tenant.

BIG-IP + TMOS timeline2004
BIG-IP softwareBIG-IP 9.0 · 2004
Operating systemTMOS (Linux host + TMM)

TMOS is introduced. System management moves from BSD to Linux, and the Traffic Management Microkernel (TMM) is created to talk to the hardware. From here, the hardware is the 'BIG-IP platform' and the software is 'TMOS'.

✓ release date on F5's record

Release dates from F5's records (K33062581, K9412); EoSD/EoTS from F5 K5903 (software support policy). EoSD and EoTS are the software milestones and coincide under the current policy; 'End of Sale' is a hardware term. BIG-IP Next (18-20) is discontinued and excluded.

From BIG-IP 12.0 the card also carries the support lifecycle: the End of Software Development (EoSD) and End of Technical Support (EoTS) dates for the branch, straight from F5's software support policy (K5903). Branches already past EoTS are dimmed as end-of-life; the still-supported ones are highlighted, and the nearest EoTS dates are flagged amber as an upgrade reminder. (These two are the software milestones and coincide under the current policy; End of Sale is a hardware term, so it does not belong on a software-version line.)

Two things on the timeline are worth calling out. First, from BIG-IP 12.0 (2015) F5 adopted the alternating model that still holds: a Major Release (x.0.0) followed by a Long-Term Stability Release (x.1.0) that most sites actually run. Second, the version numbers jump straight from 17 to 21. That gap is not a mistake and it is not skipped for superstition: 18 through 20 belonged to BIG-IP Next, a separate re-architecture that F5 has since discontinued (the final BIG-IP Next 20.3 reached end of life on 30 April 2025), choosing instead to modernize the TMOS line and resume it at 21.0.

The dates here are year-level on purpose. The release dates for 12.0 and later come from F5's own release records (K33062581, the TMOS Software Release Date Information, and K9412, the BIG-IP release matrix); the 2004 origin of TMOS comes from F5's company history; and the intermediate branches that are now end-of-life carry their widely documented release year. Nothing here is read from a live system.

This series, in order

This article opens the series BIG-IP and F5OS versions and upgrades. Its timeline shows where each version sits; the parts take the practical questions in order: whether you are upgrading or updating, what to do when an upgraded box will not load its configuration, what the newest line changed in operations and in access, and the F5OS layer the newer hardware runs underneath.

  1. BIG-IP Upgrade vs Update: Why the Distinction Decides Whether the License Date Is Checked. Which part of the version number changes decides whether the service check date is enforced at all.
  2. Recovering a BIG-IP That Won't Load Its Config After an Upgrade. The upgraded box that boots but never loads its configuration, and the reactivation that resets the date.
  3. The BIG-IP 21.x Ops Story: In-Place Upgrades, a 64-Bit Control Plane, and BigD at Scale. In-place upgrades with a dry run, a 64-bit control plane, and a monitoring daemon built for scale.
  4. BIG-IP 21.x: what changed, and why there is no version 18, 19, or 20. Why three version numbers were skipped, the lifecycle rules to check first, and a themed tour of what the new line delivers.
  5. Access and Identity in BIG-IP 21.1: DCR, Native SAML, and IPsec Comes Home. Dynamic client registration, native through the system browser, and tunnels in the Edge Client.
  6. F5OS 2.0 From the Tenant's Seat: Cloud-Init, Per-Port RRDAG, and Q-in-Q. The platform release the newest BIG-IP assumes, seen from the tenant's seat: cloud-init, per-port RRDAG and Q-in-Q.
  7. The three states an F5OS tenant can be in. Configured, provisioned, deployed: the three tenant states, and why changing vCPU or memory means going backwards.