Do these sentences indicate same meaning?

“The changes are to be updated” implies that a plan exists to update, while “The changes have to be updated” implies that changes need to be made, but a plan does not yet exist.

In my opinion, “The website should be tested” is closer in meaning to “The website has to be tested” than “is to be tested” because it implies a necessity.

What @Seelix said. Have/Has to indicate requirements. Is/Are plans.

Yes, @Seelix summed it up. If it is still confusing let us know your first language and maybe someone can explain it in that language.

@JLeslie : Hindi is my first language. English is second one.

Do you still need help with the sentences? I don’t speak Hindi, but other people here might.

@JLeslie: Actually, I had posted this question on one site & someone answered this questions as,
“The changes have to be updated. ...
The website has to be tested on all browsers.”
One meaning: must.

These have to do with a requirement, an obligation, and they mean:

The changes must be updated. (Someone must update the changes.)

The websites must be tested on all browsers. (Someone must test the websites on all browsers.)

——-
“The changes are to be updated. ...
The website is to be tested on all browsers.”
Two meanings: must; will

The first meaning is the same as shown above:

The changes must be updated. (Someone must update the changes.)

The websites must be tested on all browsers. (Someone must test the websites on all browsers.)

The second meaning is different, and it has a little of the sense of being ready:

The changes will be updated. (Someone will eventually update them; they are ready to be updated.)

The website will be tested on all browsers. (Someone will eventually test it; it is ready to be tested.)

———

“also written simply by using should be”
Two meanings: advisable; expected.

So, I have to make sure it’s correct or not.

@lessonenglish The word “have” is a little tricky. It can mean need and it can mean must. The changes have to be updated, you might be best to clarify. For instance, the changes have to be updated before we can do any more work. The changes have to be updated, but we can still continue working. One implies an immediate need, the other a need some time soon.

The changes are to be updated, implies a future plan already scheduled. But, as I think about it, depending on the context it can mean a recommendation. The changes are to be updated every two weeks. It would depend who is saying it. If my boss said it, I would think he is telling me how often I am expected to enter the changes.

The context really matterss a lot. It is difficult, I completely understand. If I was translating into Spanish I would clarify what I mean by being specific in the sentence or paragraph with more description. Actually, I would in English also. A simple sentence is not enough, too many ways to interpret it.

@JLeslie : Oh! Understood. Thank you very much! :D

The “is to be” construction can have an imperative feel (especially in British usage) even though it is a simple passive sentence. If you hear “Your bed is to be made and your room tidied in five minutes” and “You are to be out the door by three o’clock,” you understand that these are not merely expressions of a plan or a description of an inevitable future activity. You know that YOU must make your bed and tidy your room in five minutes and be out the door by three. It is like an unarguable command: the future action is so certain that it can be expressed in the passive because there is simply no room for any alternative.

So the context or situation and also the manner of delivery affect how these sentences are understood.

Let me also make a comment on content, however, since as a professional editor at a high-tech American corporation I have edited quantities of technical documentation written in India. In a technical writing environment where sentences like these would be found, you would not make sense if you wrote “The changes are to be updated.” The changes are the update. The records or queues or messages or whatever is to be updated is updated with the changes, or the changes are applied to them. But it is not the changes that are updated. Updating means making changes. (Also, never, ever say “updation.”)

Listen to @Jeruba she makes a very good point about the changes most likely being the actual updates.

@Jeruba would there ever be a case where a change would not be the actual update thoough? For instance at a retail store, changes might be being made to the register system, but the changes are not updated, or downloaded, until 4am eastern. Would that make sense.

The change might not be the update, @JLeslie, but an update would be a change. And it will be true in any case that the change is not what gets updated. The thing being updated is whatever the change is being made to.

In the situation you describe, there might be local jargon to the effect that you proposed, or they might say the changes are not posted (applied) until a certain time. Industries and even individual workplaces typically have their own special lingo, and learning it is part of mastering the job. So I can’t say that no one uses the term as it appears in your example.

But content pertaining to testing websites on all browsers clearly indicates a high-tech environment. Going by the meanings of the words and also their use in that environment, I would say unequivocally that changes are not updated because “to update” means to make a change in order to make something more current or correct.

@Jeruba I see, that makes sense to me. It depends on the audience. I think like a layman regarding these things, not a techy.