Due to a few issues with the ship-based technology compatibility plugin, which might have been the cause for some of the server lag players have been reporting recently, this plugin is temporarily disabled. Just to clarify - This is done only to determine whether or not that plugin itself was the cause of lag, and disabling the plugin permanently is not in our plans. Meanwhile, the ID-based technerf remains active and it's only the ship-based technerf which is disabled.
The plugin will remain offline for 1 week, but will be turned back on afterwards with the possible fixes included, so if you're planing on making any new ships during this time, check the ship compatibility chart on Wiki to make sure you won't find your ship in conflict with that plugin once it's reenabled.
The plugin is back up and running. For more details on both techcompat and shipcompat plugins, visit this thread. Additionally, use the appropriate bug report thread in case of spotting any possible bugs with the new plugin.
Furthermore, it's worth noting that as it turns out, the shipcompat was not the cause of the recent lags players have been experiencing, but regardless, the plugin is completely rewritten to allow a better performance and a more flexible control system. On top of that, the inability to use Gallic engines on Sirian ships and vice versa has been a major debate among the community since the idea was revealed, and rest assured, the dev team has not ignored your concern and that loss is already compensated in update 6, which will be released Soon™. There are also a good number of new custom engine effects planned, which may or may not make it for update 6, but hopefully they will.