Joining Date Confusion: How to Explain My 4-Year Tenure with a Newly Registered Company?

I have been working in a company for the past 4 years, but the company recently got registered as a Pvt. Ltd. in 2017. In that case, what will be my joining date? Do I need to provide two different offer letters from the company for my date of joining to other employers, or will one offer letter suffice to explain my 4 years of employment with this current company to other employers? Please help.

Impact of Company Registration on Employment Dates

Let me be clear, is it like joining an unregistered company and later on this was registered and continued its business with the same employees as in the past? A change in the status of the employer does not impact a change in the joining time of its employees. Of course, in instances of employees continuing but with a change in the names of the entity (unregistered to registered), it might. This can be overcome by issuing a formal letter to everyone stating that the continuity of service is validated without any break. This formality would ensure full entitlement in respect of EPF/EPS, gratuity, bonus, confirmation, increments, and promotions. However, it is inevitable and essential to appropriately arrange a name change, if any, in statutory documentation in registrations such as EPFO, ESI, PT, PAN/TAN/TIN, GST/Labour licenses, MSME, etc.