I was able to install Mojave in an IDE (in an extenal 2.5" box) HD (It is now an APFS volume). Takes time to boot, then works fine (AFAIK).
Unfortunately, that HD is invisible from my El Capitan internl boot SSD.
I do not checked if HFS+ formated volumes (my archives) are visible from Mojave, but I suppose they are (confirmation, someone ?)
BTW: to simply install Mojave on that empty / formated HD tooks me one hour. And 60 minutes is a very long time when you are waiting !
I nearly forgot:
Xojo 2015r1 runs fine (limited testings).
iMessage and FaceTime (I think) were used during the installation. You need to have an Apple ID to install Mojave (and I do not talk about iCloud). Two Password
Fortunately, nor an Apple Watch nor an iPhone was mandatory.
My internal SSD is 250GB and nearly always full (arouns 20 to 50 Free GB). Before upgrading, I will baclup that data. So any new mac OS is a non sense excepted the current one.
On the other way, my most recent Xojo license is for 2015r1.
After a bit of thinking, I came to the conclusion that excepted if I have to upgrade (am forced foe some reason to update), I will stay as it is right now. Getting a brand new Apple laptop is a way to be forced to use Mojave (probably, and for me).
Nota: Is trongly dislike Apples direction (201x) for mac OS.
Beside bugs, I was able for decades to use macOS the way I want and love. Changing Finder grids was boring, changing keyboard shortcuts (in the View Menu) too, changing the way the green button (left of windows) behave, and so on. Not talking about where windows are displayed on multiple screens and too far features (changes on old or brand new ones *) are particularly boring.
The way a senior vice-president make debug (and gives order to change decade old behaviors because he do not know them) - this is IMHO - is particuliarly bad.
All of these reasons (and probably more that I actually forgot) does not let me think I have to upgrade (fast / until I cannot continue to use old mac OS).
Actually, my OS troubles comes with the 10.2 to 10.3 transition (Finder Desktop invisible files), and Xojo was not really good for me (I have to build a simple projedt nearly for every new feature I want to add in main projects until they works there). Sometimes, the project works fine, so I save it, shut down, back home to discover that after I powered on my laptop that the new feature (or another) is no more working. Very boring.
I reported a Xojo issue with transparent images under Mojave.
( I had to do some widespread refactoring to move away from white=transparent)
It was a serious (and immediately obvious to the customer) issue.
I have thousands of users, and many of them in turn run businesses using the software.
Since Mojave came out, only 3 people reported this to me, and 2 of them ran into it because they had bought a new Mac due to their old one dying.
Based only on my limited feedback, I strongly suspect that Mojave is not being installed by many people at the moment.
Some people (me included), with time, stop to install the first release and wait for .2 or .2 or before installing a new macOS version.
Also: I do not do that with El Capitan, and this is a bit difficult to do, but installing the last .x update of a macOS is also a bit dangerous. On some old macOS, that version contained preliminary work of what was installed in the next major update: I had some troubles (I forgot what troubles) that were removed in the next major version.
In fact, I do not have a 2.5" SSD inside, but an SSD in the memory chip format. That MacBook Pro 13" is 4 years old, but do not have an SSD in the 2.5" hardware format. But I am thinking at an external SSD (~ 500 GB) and using it as a boot drive, letting the internal one as an every day data storage, eventually.
MacWay (Strasbourg) had an Action: Série 860 EVO, Disque SSD 2,5", 500 Go / SATA III, 89,90 .
That action is over.
I did use El Capitan until today on my MacBook Pro late 2013 with SSD. I just update to Mojave.
I have 2 partitions on my SSD, one for system, applications and users. The second partition contains all my documents (photos, Xojo projets, .doc, .xls, etc. ).
The first partition (system) did automatically change to APFS. The second partition (my Documents) stay in HFS.
Xojo project (which are second parttion the HFS) are longer to open since I’m running Mojave.
Should I change my second partition to APFS ? Is it faster ? is it safer ?
@Jean-Yves Pochez Well you can take snapshots of your volume, but perhaps more interesting is the possibility of creating another logical volume on the same disk. It is like having a new partition but without actually partitionning your drive. It can be useful if you want to install a beta system that you can quickly get rid of.