dragonfly convert (filter) fails after dragonfly upgrade

[psal0]

I have a site where I am this in one of my templates:

<img src="{{ company.image.url | resize: '600x500', filters: ' -gravity center -extent 800x -bordercolor white -border 30' }}" alt="{{ company.name }}" data-no-retina="">

I have been using that template since many years with older versions of locomotivecms successfully.

Now, after the update to the latest version, the template shows broken images, although the image url rendered in the template looks correct.
The same site synced and run locally shows an error:

DRAGONFLY: caught error - The convert processor is deprecated for better security - use Dragonfly::ImageMagick::Commands.convert(content, args, opts) instead.
DRAGONFLY: GET /steam/dynamic/W1siZmYiLCIvVXNlcnMvc2Fsb21vbi9NaW5kc2NhcGVWZW50dXJlc0Nsb3VkL1dlYkRldmVsb3BtZW50L2xvY29tb3RpdmVjbXNfc2l0ZXMvazRzb2NhbC9wdWJsaWMvc2FtcGxlcy9fcHJvZHVjdGlvbi9jb250ZW50X2VudHJpZXMvbG9nby1yaXNpbmctd2luZXMtY29sbGVjdGl2ZS1zdGFja2VkLnBuZyJdLFsicCIsInRodW1iIiwiNjAweDUwMCJdLFsicCIsImNvbnZlcnQiLCIgLWdyYXZpdHkgY2VudGVyIC1leHRlbnQgODAweCAtYm9yZGVyY29sb3Igd2hpdGUgLWJvcmRlciAzMCJdXQ/2ad7ca522bdcad6f/logo-rising-wines-collective-stacked.png 500

[psal0]

Its dragonfly version 1.4.0: https://github.com/markevans/dragonfly/blob/master/History.md