I learned that your company has been acquired by a larger enterprise,
and we have been told that everything shall remain the same for us.
This is management jargon. And it cannot be factually correct. Companies acquire other companies in order to make use of their technology, their patents, the knowhow their employees possess, the brand value that the company enjoys. The acquiring company will bring its own expertise into play in order to increase market share, take the company into new markets, introduce it to existing clients of the acquiring company.
All of the above are good things, but they show that:
everything shall remain the same for us
is just not possible.
Now let's come to the difficult part. The most common reason to acquire another company include synergies between the two companies, the acquiree company is not being well-run, and there is potential for cost cutting.
The synergy reason is the most compelling from a growth perspective, but is the most difficult to realize in practice due to culture clashes, knowledge silo, operating and legal issues, and a hundred other small things.
The acquiree company not being well-run, and the cost-cutting are what get picked up in the short term. When a company is being set up they tend to acquire a lot of people who are needed to put the departments and processes in place. As they do their job, they get rewarded with C-level positions, and can't be asked to leave without causing culture and morale issues.
With an acquisition, ALL positions will get looked with a fine-toothed comb, and a "strategic perspective". The top level management has the most difficulty in justifying its role, because they generally drive long term projects, and don't do hands-on work.
Either way, if they are leaving, they have been asked to leave, or been given a hint. Either way, you need to be aware yourself of what is happening.
As a Software Engineer should all this news concerns me at all?
It does. Your job could get outsourced to a vendor. Your performance might not reach the right ears. Whatever.
Also, while you should talk to your reporting manager about these issues, keep in mind that his primary role now will be to "hold the ship" together. So if he gives you a negative answer, you need to start looking out for another job immediately.
Even if he gives a positive answer, you should check out market value, understand what roles are available, what are your best career prospects, etc.
In conclusion, an acquistion is something where you always need to be careful, especially if you are in the company that has been acquired.