In the upgrade documentation I see that suggested upgrade path to 0.13.x is from 0.12.x only.
Do you support upgrading from 0.11.x as well?
If yes, do the steps are the same as in 12->13 upgrade?
If not, can you advice how can I do it?
Would wait Kong teams direct answer here, but my personal preference has been to upgrade from major version to major version 1 step at a time via migrations. Taking the latest iteration of whatever stepping stone major versions you have to use as a bridge to reach the final version. Can’t say I have ever jumped major versions like you are trying to do though, nor do I know of the feasibility or risks associated. My personal reason for going major to major 1 step at a time is because they do a good job with documenting all risks and changes version by version so you are less likely on your end to forget a config change and mess things up if you take it incrementally. Just my 2 cents.
The Kong migrations are meant to be incremental and should be able to upgrade a major version to any other greater major version (skipping some on the way). Updating the Nginx template (if you have one) will be a little bit harder since you’d need to make all the necessary changes at once, but doable.
However, @jeremyjpj0916’s advice is wise, and I would encourage you to follow it. Smaller migrations means a little more work, but can save you a lot of time down the road. Smaller, incremental steps will be less disruptive for your infrastructure, and will give you or your team more chances to catch incompatibilities if any, and better understand the impact on footprint or in your traffic. If anything, it should be easier to downgrade a single major version than two at a time, so that should be reason enough already.
Thanks for your responses.