Something to look forward to: Some expected Samsung to share more public information about the phone at CES but that doesn’t appear to be in the cards. Perhaps we’ll get more details at Mobile World Congress next month?

Samsung engineers have been working for years on a foldable smartphone concept, developing cutting-edge technologies like the Infinity Flex Display and ironing out the multitude of kinks associated with bending electronics.

According to one report out of CES, there’s still additional work to be done.

The Korean Herald reports that Samsung is showcasing the foldable phone prototype to select clients behind closed doors. One high-level executive told the publication that when unfolded, the phone does not show any crease indicating it has been bent, adding that the device’s screen felt smooth to the touch.

“However, completely folding the device will lead to breakage,” the executive said.

As such, Samsung is testing methods that will keep the sides slightly lifted when folded.

The executive said the prototype they were shown does leave a crease mark when being folded but noted that the issue will be fixed in the final consumer version.

Samsung publicly demonstrated its Infinity Flex Display for the first time last November although it did so under the guise of very dim lights and an external chassis to hide the elements of the design.