# UCS file migration on differing OS versions **URL:** \ **Category:** Technical Forums\ **Tags:** ucs, gtm-dns\ **Created:** [June 25, 2026, 2:58am UTC](https://community.f5.com/t/ucs-file-migration-on-differing-os-versions/77225 "2026-06-25T02:58:13Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![mtfeliciano](https://d1p9zq3aats0t8.cloudfront.net/user_avatar/community.f5.com/mtfeliciano/32/33616_2.png) [@mtfeliciano](https://community.f5.com/u/mtfeliciano)\ **Post date:** [June 25, 2026, 2:58am UTC](https://community.f5.com/t/ucs-file-migration-on-differing-os-versions/77225/1 "2026-06-25T02:58:13Z")
We are currently upgrading the F5 load balancers of our customer, from iSeries, to rSeries. **old F5 load balancers:** - model: BIG-IP i5600 (C119) - OS: 12.1.x (either 12.1.2 Hotfix HF2 2.0.276 or 12.1.4 Final 0.0.8) - GTM / DNS configurations: enabled **new F5 load balancers:** - model: rSeries (2600 and 4800) - OS: 17.5.1.6 - GTM / DNS configurations: no longer needed, as per our customer questions: 1. Noting the OS versions of the old and new F5 load balancers… Is this the ideal OS upgrade sequence? (based on F5 K13845) **BIG-IP 12.x \> BIG-IP 14.x \> BIG-IP 15.x or BIG-IP 16.x \> BIG-IP 17.x** 2. BIG-IP 14.x is no longer available in F5’s Downloads website. Are there any other methods for obtaining a copy of BIG-IP 14.x? 3. About UCS file migration, from old to new F5 load balancers: Would there be any risks, configuration-wise, if we do the following steps? - we take the UCS file from the old F5 load balancer, which is running on BIG-IP 12.x - we import and load that UCS file onto the new lab F5 load balancer, which is running on BIG-IP 17.x 4. Since our customer advised that they will no longer need any GTM / DNS configurations on their new F5 load balancer: Should we delete the **bigip\_gtm.conf** file from the contents of the UCS file of the old F5 load balancer, before migrating to the new F5 load balancer? ---
**Author:** ![Daniel\_Wolf](https://d1p9zq3aats0t8.cloudfront.net/user_avatar/community.f5.com/daniel_wolf/32/1119_2.png) [@Daniel\_Wolf](https://community.f5.com/u/Daniel_Wolf)\ **Post date:** [June 26, 2026, 5:41am UTC](https://community.f5.com/t/ucs-file-migration-on-differing-os-versions/77225/2 "2026-06-26T05:41:21Z")
Hi @mtfeliciano , 1. The fact that your customer is still on 12.x should tell you, that they didn’t care about their BIG-IP for more than 8 years. Ticking bomb… Your update sequence is correct. 2. Try your luck opening a support case. I doubt a customer running on 12.x has an active support contract… 3. Make sure you have the Masterkey: [myF5](https://my.f5.com/manage/s/article/K000152853) and that you prepare the UCS archive for migration from iSeries for rSeries: [myF5](https://my.f5.com/manage/s/article/K000160543) 4. Remove the GTM config on the iSeries before the migration. Good luck ---
**Author:** ![Daniel\_Wolf](https://d1p9zq3aats0t8.cloudfront.net/user_avatar/community.f5.com/daniel_wolf/32/1119_2.png) [@Daniel\_Wolf](https://community.f5.com/u/Daniel_Wolf)\ **Post date:** [June 26, 2026, 5:48am UTC](https://community.f5.com/t/ucs-file-migration-on-differing-os-versions/77225/3 "2026-06-26T05:48:31Z")
And for 3. Don’t take an UCS on 12 and restore it on 17. Just don’t! ---
**Author:** ![Paulius](https://d1p9zq3aats0t8.cloudfront.net/user_avatar/community.f5.com/paulius/32/21698_2.png) [@Paulius](https://community.f5.com/u/Paulius)\ **Post date:** [June 26, 2026, 2:24pm UTC](https://community.f5.com/t/ucs-file-migration-on-differing-os-versions/77225/4 "2026-06-26T14:24:28Z")
You’re better off migrating the configuration a bit manually using the scf file or grabbing the configuration via CLI. I would indeed remove the GTM configuration before migrating to the iSeries. ---
**Author:** ![Mohamed\_Ahmed\_Kansoh](https://d1p9zq3aats0t8.cloudfront.net/user_avatar/community.f5.com/mohamed_ahmed_kansoh/32/10886_2.png) [@Mohamed\_Ahmed\_Kansoh](https://community.f5.com/u/Mohamed_Ahmed_Kansoh)\ **Post date:** [July 6, 2026, 5:46pm UTC](https://community.f5.com/t/ucs-file-migration-on-differing-os-versions/77225/5 "2026-07-06T17:46:28Z")
Hello, Since the new rSeries isn’t in production yet, so you can try, so : First:  in your Upgrade path, avoid upgrading to v16 it’s not supported over F5OS platforms, so use V15  so it shoud be ( V12 --\> V14 --\> V15 --\> V17.1.x ) Second:  you need to request these series of Old versions from F5 Support, so contac t them if you have a valid Contract. Third: If you couldn’t get them you will do some work manually…  - get bigip.conf file from the old devies, and ( bigip\_base.conf  if you want to migrate with the same L2 configs like Vlans , Trunks , selfips )  - open the new TMOS tenant that inside the rSeries and then merge configurations from terminal, use this article > **[myF5](https://my.f5.com/manage/s/article/K81271448#:~:text=save%20/sys%20config-,Merging%20a%20BIG%2DIP%20configuration%20from%20the%20terminal%20into%20the%20running%20configuration,-To%20load%20the)** - When you encounter errors duo to missing some dependances in some Configuration objecs like Virtual servers, go and add them manully via GUI, Like downloading ( SSL Certificates and Private Keys ) make sure to put them before anything on the new tenant. - then start with mergind ( Nodes, Monitors, irules , Profiles , pools , VIPs … ) - Avoid restoring UCS file on V17 directly. - As I see you don’t need GTM configs anymore, so don’t merge or add anything from bigip\_gtm.conf Good luck !