Can we do static linking with third-party librarires using LGPL licence?

[Awareness]

We can't do static linking with Qt librarires if we are using LGPL licence,if I understood right.What about doing static linking with third-party librarires using LGPL licence?

Also,I heard that all Qt commercial licenses are perpetual,and they include first 12 months of maintenance and support.So,if we buy a commercial licence now,can we freely(without paying additional money) upgrade to commercial Qt 6.0 when it becomes available?

[Uwe]

We can't do static linking with Qt librarires if we are using LGPL licence,...

Of course you can - but it has implications on what you have to do with your own code. The LGPL and its effects is explained on many pages in the Web - you won't get anything better by asking here.
LPGPL is LGPL no matter if it is Qt or any other 3rd party library, but the Qt commercial license is specific - if you want to know more about I recommend to read it.

But as soon as you are using any other 3rd party library that is LGPL you probably don't want to link your application statically and I don't see many reasons for buying a commercial license.

Uwe

[wysota]

So,if we buy a commercial licence now,can we freely(without paying additional money) upgrade to commercial Qt 6.0 when it becomes available?

If the current trend continues then Qt 6.0 will be available around 2020 or later so you shouldn't really bother your mind with that problem right now.

[Awareness]

Thanks for your answers.