Finally got my oath letter. 
One more thing that I would like to tell that I called call center a day or two ago and informed that my ECAS shows that date and time of the oath. He confirmed of the same. Following which I told him that I have not recieved the oath letter yet. He informed me that oath letter is not necessary, he emailed me list of the things that I have to bring at the time of my oath should I don't receive the letter before oath. Here is the list of things that you need to bring if you do receive your oath letter but you know the date and time of the oath.
Required documents for the citizenship ceremony
When you attend the citizenship ceremony, you must bring the following documents with you:
- (If available) The Notice to appear to take the oath of citizenship letter,
- Two pieces of personal identification, one of which has your photograph and signature on it (e.g. driver’s license, health card, passport, etc),
- All your original documents that support your citizenship application (e.g., Immigration Record of Landing (IMM 1000) or Confirmation of Permanent Residence (IMM 5292 or IMM 5688), birth certificate, etc.),
- Your Permanent Resident card, if you have one,
- All passports and travel documents in your possession (current and expired), and
- (Optional) A holy book of your choice, if you wish to use one to swear on for the Oath of Citizenship.
If you do not bring the required documents, the officer at the local CIC office will decide if you can attend the citizenship ceremony or not.
One more thing that I would like to tell that I called call center a day or two ago and informed that my ECAS shows that date and time of the oath. He confirmed of the same. Following which I told him that I have not recieved the oath letter yet. He informed me that oath letter is not necessary, he emailed me list of the things that I have to bring at the time of my oath should I don't receive the letter before oath. Here is the list of things that you need to bring if you do receive your oath letter but you know the date and time of the oath.
Required documents for the citizenship ceremony
When you attend the citizenship ceremony, you must bring the following documents with you:
- (If available) The Notice to appear to take the oath of citizenship letter,
- Two pieces of personal identification, one of which has your photograph and signature on it (e.g. driver’s license, health card, passport, etc),
- All your original documents that support your citizenship application (e.g., Immigration Record of Landing (IMM 1000) or Confirmation of Permanent Residence (IMM 5292 or IMM 5688), birth certificate, etc.),
- Your Permanent Resident card, if you have one,
- All passports and travel documents in your possession (current and expired), and
- (Optional) A holy book of your choice, if you wish to use one to swear on for the Oath of Citizenship.
If you do not bring the required documents, the officer at the local CIC office will decide if you can attend the citizenship ceremony or not.