[sc00ter]

CarrierWave appears to support Rails 4; the rest are not doing anything special other than making jquery js acripts available in the asset pipline without manually installing them, so shouldn't cause any issues.

You'll have a bit of work to do to migrate to strong parameters, but you can always add the protected_attributes gem back to re-enable support for attr_accessible.

I'd suggest checking out the Rails 4 migration RailsCast.

[aaronbrethorst]

I've been using Carrierwave with Rails 4 RCs and haven't run into any trouble with it.

[jpdoctor]

Thank you for this info.