[StefanM]

I noticed that often the User Agent of JD contains an outdated version of Firefox.

Some webpages don't like that...

I would recommend to always use the latest User Agent version of e.g. Firefox.
And I would suggest to implement an option (in advanced settings) that the user can enter their own User Agent string.

For the time being, only with some Hoster PlugIns the user can define that string. But when I look e.g. at the VK.com PlugIn, default settings read

Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:46.0) Gecko/20100101 Firefox/46.0

Or is 46.0 being used for a reason?

[Jiaz]

Originally Posted by StefanM

I would recommend to always use the latest User Agent version of e.g. Firefox.

There is a reason we don't update default UA thoughtless as this easily can and will break many plugins because they change behaviour/html/js depending on UA. For example instagram recently started to behave differently depending on old/newer UA, which broke account support.

Originally Posted by StefanM

And I would suggest to implement an option (in advanced settings) that the user can enter their own User Agent string.

Currently there are no plans for this because there is no need to and custom/different UA can easily break plugins, for example some plugins/api do require a special UA to work properly, and see my comment above.

[Jiaz]

Originally Posted by StefanM

Or is 46.0 being used for a reason?

In case a plugin uses a customized UA, there is a reason. for example different behaviour/layout/js.
Of course it might be outdated and newer UA might work but there is no need to change it when it's working.

[Jiaz]

Originally Posted by StefanM

Some webpages don't like that...

For example? We're happy to check and update accordingly

[StefanM]

Originally Posted by Jiaz

For example? We're happy to check and update accordingly

In fact, VK.com is an example.
With v46.0 you sometimes get unwanted popups, asking you to use another browser or you cannot even access the page at all.

Haven't observed this in JD so far, but I did observe this with an outdated Firefox browsers v56.x.x. And it may very well have been the reason for some problems already - without knowing it for sure...

Another reason, why I would avoid using the same outdated version for a longer period of time is the following:

As you know, many hosters try to detect the use of download managers and then block them.

Now, if JD uses e.g. Firefox 46.0 User Agent for a longer period of time, some IT guys at e.g. VK.com may notice that and know, that people are using JD instead of streaming their videos. One should try to avoid them noticing that...

An as soon as they notice that, a modification of the corresponding PlugIn is needed...

[Jiaz]

Originally Posted by StefanM

In fact, VK.com is an example.
With v46.0 you sometimes get unwanted popups, asking you to use another browser or you cannot even access the page at all.

JDownloader does not have any browser engine,so no dom/html/js/no poups/no ads...nothing. only pure http requests that must be coded in plugin.
as long as the UA does not change the behaviour/flow of the website, all good, which is the case here

[Jiaz]

Originally Posted by StefanM

As you know, many hosters try to detect the use of download managers and then block them.
Now, if JD uses e.g. Firefox 46.0 User Agent for a longer period of time, some IT guys at e.g. VK.com may notice that and know, that people are using JD instead of streaming their videos. One should try to avoid them noticing that...

You don't have to rely on UA to detect tools/bots/scripts! Even with updated UA, it only takes about 1 line of code to detect tools/bots/scripts. Just modify html, that's it. In over 14 years, I can count UA blocking happening with less than 10-20 fingers (and often the same site)

[Jiaz]

Originally Posted by StefanM

An as soon as they notice that, a modification of the corresponding PlugIn is needed...

Correct! But in that case we'll notice it (either ourselves or by reports), but if ppl just start changing UA themselves, guess who they gonna ask for help or complain when plugin breaks/fails. The many ping/pongs until ...*ah..sorry..my fault..I did experiment with different UA*.

[KCOU]

Is there a way to find out the useragent being used at the moment of use by jdownloader by looking at any option or logfile? Without third party software.

In advanced options you can see some plugins able to change from JDDEFAULT to whatever, but what is JDDEFAULT?

I'm looking for the user-agent string, not to change it.

[pspzockerscene]

Originally Posted by KCOU

Is there a way to find out the useragent being used at the moment of use by jdownloader by looking at any option or logfile? Without third party software.

Enable debug logs, then add links and/or start downloads and afterwards simply search for "User-Agent" in your logs.
You will find it in the logged http headers.

Originally Posted by KCOU

In advanced options you can see some plugins able to change from JDDEFAULT to whatever, but what is JDDEFAULT?

JDDEFAULT is the global default User-Agent which all plugins are using by default.
It can change and it is not exposed in any of our settings which is why the string "JDDEFAULT" is used in plugin settings in this case.
Currently that resembles to:

Mozilla/5.0 (Windows NT 10.0; WOW64; rv:76.0) Gecko/20100101 Firefox/76.0

It may be different depending on your OS - I haven't checked that.