Generally, yes. If your employer has changed the name of the company, you are required to demonstrate the name change and provide proof of the links between the new company and the company listed on your work permit.
Accordingly, it is recommended that if your employer changes the name of the company, that you request a signed letter detailing the name change.
There are rare cases in which you may be able to continue working under the same work permit, such as where the old and new employer are related entities, but we strongly suggest that you meet with properly qualified counsel before deciding to not refrain from requesting a new work permit.
If you are a foreign worker and your employer has changed names and you need advice with respect to documentation to demonstrate the link, please contact Toronto immigration and employment lawyers, Sultan Lawyers, at (416) 214-5111 or via email to firstname.lastname@example.org.