Which of the following is correct:
Journalists' Solidarity Forum
Journalist Solidarity Forum
Which of the following is correct:
Journalists' Solidarity Forum
Journalist Solidarity Forum
If you are referring to the formal name of an organisation, website, journal, etc., then you should follow the style adopted by the organisation, publication, etc..
If it is not the formal name of recognised group or publication, then it is a mere description, and it is therefore inappropriate to capitalise the description because it is not a recognised name.
Before answering, I did search to check whether is it a formal recognised name, but found nothing so I am basing my answer on the assumption that it is not a recognised name.
I assume that you are referring to:
a solidarity forum for/of journalists, or to
a forum for the solidarity of journalists.
In either case, the solidarity forum belongs to the journalists, so you need to use the plural form (more than one journalist) and the possesive form (belonging to). Therefore:
[You might find English Language Learners better for this kind of question.]
Journalists' Solidarity Forum
This uses Journalist in the plural genitive form.
Journalist Solidarity Forum
This uses Journalist as a noun-adjunct, that is to say using a noun sense as an adjective or adverb (in this case an adjective; modifying the noun phrase "solidarity forum").
As such, both are correct, and both mean much the same thing. Both forms are found in practice.
A more doubtful form would be:
? Journalists Solidarity Forum
This uses a plural as a noun adjunct, which many would argue was incorrect but is sometimes found in names that started in the first form, and then lost the apostrophe at some point. In all though, best avoided.
Now, either would be grammatically correct and of the same meaning, but the latter form is becoming more common generally as genitives are less and less common in names (a matter of fashion more than of correctness), so I'd lean toward recommending it. If used descriptively rather than a title, I'd favour the former as less ambiguous in possible parsing; that is while one could both say "PEN International serves as a journalist solidarity forum as well as supporting other writers" and "PEN International serves as a journalists' solidarity forum as well as supporting other writers" the latter is more graceful.