And in general, difference between have been and had been?

I'll answer this because the two previous questions depend on what you want to express. Just a note before-hand, the best site for English grammar I know is ego4u.

First the quick answer:

• have been --> present perfect progressive: an action that took place in the past and continued until recently or is still continuing
• had been --> [past perfect progressive]: an action that started in the past and continued until some point in time in the past

Longer answer:

Conceptually, there are a limited number of possible tenses. Here is a picture from ego4u

Let's say you want to tell a story. There are the static states you can describe

• Something is in a certain state right now e.g the person is alive, the table is on the second floor, life is great --> that's the simple present
• In the past something happened and the action was completed e.g I stood there, the pool was filled, the plane got loud --> that's the simple past
• A thing is in the future or there is an intent to do something in the future e.g we will be there, the train will be on time, they are going to have a party in the hotel --> simple future. Notice the use of will and going to. Those are two ways to express the simple future.

So, now that we've expressed a state, something that is unchanging, we would like to describe changing actions are particular strips in time:

• Actions that are currently taking place and ongoing e.g the person is living, the table is standing on the second floor, life is going great --> present progressive. Notice the difference from simple present above. The action is ongoing.
• A thing that's going on in the past: I was standing there, the pool was being filled, the plane was getting loud --> past progressive. Again, compare with simple past from above
• Something in the future is changing: we will be standing there, the train will be waiting on time, they are going to be partying in the hotel --> future progressive

Alright, we have expressed points in time both static and changing, but what about actions that happen just before those points in time? They concluded or may be still happening. We call those "perfect" tenses.

• the person has lived here for ages, the table has stood on the second floor, life has been great --> present perfect
• I had stood there, the pool had been filled, the plane had gotten loud --> past perfect aka something that happened before a thing in the past
• we will have stood there, the train will have waited on time, they will have partied in the hotel --> future perfect = an future past action or action that will be the past in the future

And finally, if we look at the diagram we see one last group of progressives - perfect progressive. Remember, progressive describe something that's still ongoing at the point in time. You may ask why they are needed when the "perfect" overlaps with the progressive - something that started before a point in time and continues to happen.
Well, that difference might be lost with time as they tend to become less and less important. A grammar purist might disagree but in colloquial English, my experience shows less and less people can tell the difference and I do have to look it up:

The difference between "perfect" and "perfect progressive" is the focus of the tense. "Perfect" makes the result important and "perfect progressive" makes the duration or fluidity / continuity of the action important. I invite you to read this page on Present Perfect Simple vs Present Perfect Progressive. It explains it quite well.

Hopefully that will help you answer your two first questions.

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There still are phones that can do this, and from 2027, all phones sold in the EU must allow user-replacement of batteries.

Fairphone?

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