This is from CIC's official website:
a reference or experience letter from the employer
should be an official document printed on company letterhead (must include the applicant’s name, the company’s contact information [address, telephone number and e-mail address], and the name, title and signature of the immediate supervisor or personnel officer at the company);
should indicate all positions held while employed at the company and must include the following details: job title, duties and responsibilities, job status (if current job), dates worked for the company, number of work hours per week and annual salary plus benefits.
Pay close attention to the wording like "should" or "must" especially from CIC.
Hope this helps.
Good luck !