The Strike which began on April 19th by the Public Service Alliance of Canada (PSAC) has ended with the PSAC and the Federal Government reaching a tentative agreement. The PSAC includes IRCC employees as well.
The IRCC website says that there will be some service impacts in the coming days and weeks as the employees return to full capacity.
During the strike one could still apply online or through mail. However, there was delay in processing due to limited capacity. Some of the other services impacted were:
Biometrics in Canada for which the time limit was automatically extended to 60 days from 30 and the original biometric instruction letter was sufficient and no new letter was required,
Citizenship events are postponed and new dates will be informed,
Passport services may experience a delay outside of Canada,
Contacting the IRCC through any means including the webform will experience delayed response.
Now that the strike is over, things are expected to come back to normal in a few days.