1.5. will be able to use Your current bookmarks.
Your bookmarks are a file with the name bookmarks.html and that is in Your profile. All K-Meleon from before 0.6 until 1.5. can use that file and format.
Always create & keep a backup of bookmarks.html and other profile data at a safe place. Especially do it before an update
p.s. ha ha, Your English is as good as ours.
alain speaks French & I speak German.
We only pretend to understand en-US.
& I did not remember which K-Meleons have the menu item in File.
1.5. version does not exist in Italian.
The main advantage of 1.5 is that it has better layer called tabs and better session support. It also has better Preferences menu and more Preferences.
Your 1.1.5 can be updated easily to 1.1.6 which exists in it-IT
(IT is where Your IP comes from - so I think You may want K-Meleon 1.1.6.it-IT).
But I do not remember whether that has better session support.
1.1.6 is the same stable version a Yours. It will not do damage to Your profile.
And You can use Your language if You speak Italian.
If You want the better sessions plugin You can update to 1.5.3.
But it does not exist in Italian. AFAIK It has a compatibility macro to handle older profile data. Like any K-Meleon it can use Your bookmarks.html.
In both cases You can update the engine to GRenderingEngine 22.214.171.124. It is explained in this thread
and the download is here at extension central
The mentioned updater is for all 1.1 and all 1.5 versions. It does not affect bookmarks or any other of Your profile data.
BTW. AFAIK You can have both Italian 1.1.6 and new English 1.5.3 next to each other if You install 1.5 into a new extra directory without multi user support or a new extra directory & create an new extra profile for it.