For a new project, we will start with Informix 11.70 Innovator-C edition, which is free. Later we plant to migrate to Growth edition, if performance requires it, and finnaly to Ultimate edition if we have enough clients.
Q1: My question is, that if I don’t want to upgrade to a different version, like 11.70xC3 -> 11.70xC4, but to the same version of a different licenced edition, is it sufficient to simply stop the engine, replace the binaries with the new edition, then start it?
The migration guide only mentions version upgrades.
Q2: If the Innovator-C version is different in version from the future newest Growth edition, do I simply follow the Migration guide, like I would if I would do a Growth 11.70xC3 => Growth 11.70xC4 update?
Q3: Is it possible to trade up from Growth Limited Use Socket License to Ultimate PVU units?
If you migrate from 11.70.FC3 IC edition to any other 11.70.FC3 edition, there is no need to do more than stop the engine and restart with the new binaries. There are several ways to get the new binaries in place before the old system is taken offline, which reduces the downtime to the time taken to go offline, switch symbolic links, and go back online.
Migrating from 11.70.FC3 Innovator-C to 11.70.FC4 Growth would be the same as any other migration between .FC3 and .FC4. In general, the minor number changes (like FC3 to FC4) do not involve ‘conversion and reversion’ (C&R). Sometimes, they do – and specifically, IIRC, there is C&R between FC3 and FC4. This is not a costly (time-consuming) process, but you do need to take it into account.
There is no technical reason why not; you would have to speak to your sales person to ensure there isn’t a legal reason, but I’d be pretty surprised if it was not possible.