"upgrade their knowledge" is a grammatically correct phrase and can be used in written English.
It means to improve or enhance one's understanding or skills in a particular area. Example: The company encourages its employees to attend regular workshops and seminars to upgrade their knowledge in their respective fields.
This shows the need for agricultural training programs that help farmers to upgrade their knowledge and obtain up-to-date information about new technologies applied in agricultural production.
EBM focuses not only on grading the strength of the evidence but also on the processes and tools that are necessary for clinicians to continually upgrade their knowledge and skills for those problems encountered in daily practice.
Unless they can upgrade their knowledge and skills -- and, in some cases, move to a new industry or location -- they face constrained economic opportunities.
Lithuanian teachers have considerable skill and experience but need to upgrade their knowledge.
They were aimed at in-service professionals who would like to refresh or upgrade their knowledge in nutrition.
Lithuanian researchers are skilled and experienced but need to upgrade their knowledge with western technology, environmental protection and market economy.
Teachers have upgraded their knowledge, skills and competencies in learning management.
The enhancing of digital technologies could be beneficial to the creative writers upgrading their knowledge on writing, sharing of experiences and publishing of their literary works.
Several trainees mentioned upgrading their knowledge about resuscitation and on the length of time to continue resuscitating a baby.
This 6 h training upgraded their knowledge and helped them to integrate first aid training in the curriculum.
Most staff that was interviewed expressed that they are not interested in changing position, they prefer to stay in their current position, but find upgrading their knowledge regularly through training very important.
