"unknown at this stage" is a correct and usable phrase in written English.
It is typically used to describe something that is not currently known, but may become known or revealed in the future. It is often used in formal or professional writing, such as in research papers or business reports. Example: The exact cause of these symptoms is unknown at this stage, but further testing and analysis may provide more information in the future.
Whether other companies with develop slot-in accessories is unknown at this stage.
It remains unknown at this stage whether the new series will follow a similar format.
Philo's next moves are unknown at this stage, although rumours suggest she will be based in London full-time with her young family.
It is also unknown at this stage what restrictions the government will put in place, once it has formulated more permanent rules.
It's unknown at this stage if the new series will follow the controversial new timeline established by JJ Abrams in the 2009 reboot.
"Whether he was pretend dead or was just lying there, or whether it was true, is all unknown at this stage but, because of that false belief, they seriously tortured the four ladies.
In the WSL region, the contribution from the lower elastic lesion layer (of unknown thickness at this stage) results in a slower initial SAW velocity value which continues to drop as the influence of the lesion layer became more dominant for higher frequency components.
Although these extensions are mathematically interesting, we have not attempted to apply such an extension here since the precise form of the putative spatial or temporal dependence is unknown, and at this stage, we anticipate that more detailed experimental data would be required to calibrate these more detailed mathematical models.
Merseyside Police said the motive behind the shooting was still unknown at this early stage.
The doctors also stressed the importance that they cannot answer any questions regarding the future, with Schumacher's condition meaning that his chances of survival remain unknown at this current stage.
How much demand there is for virtual reality remains an unknown at this nascent stage.
