macOS 10.15 Catalina on Unsupported Macs

[480951]

Yes

Is your SSD formatted APFS which is required for Catalina

Yeah, even on High Sierra I have it formatted to APFS.

 

[TimothyR734]

Yes


Yeah, even on High Sierra I have it formatted to APFS. View attachment 923060

Are you using the latest macOS Catalina Patcher vision 1.4.4

 

[Pinarek]

is there a catalina 10.15.5 Nightshift patch for the Intel HD3000 in an MBP 8,3 ? thanks for info

is ok, i have self solved this Problem.

 

[ASentientBot]

And me! Thanks!

I have a follow-up question regarding AMFI and library validation related flags. I looked them up here:
1) /Volumes/Preboot/*/Library/Preferences/SystemConfiguration/com.apple.Boot.plist
-> Kernel Flags = amfi_get_out_of_my_way=1 -no_compat_check (then changed to only -no_compat_check)
2) /Library/Preferences/SystemConfiguration/com.apple.Boot.plist
-> Kernel Flags = -no_compat_check
3) nvram
-> boot-args isn't present
4) /Library/Preferences/com.apple.security.libraryvalidation.plist
-> DisableLibraryValidation = YES

All works fine, with either setting for 1), including Skype and zoom. For those I've used tccplus before to allow microphone and camera usage. I'm using an MBP5,2 with (non-metal) NVIDIA 9600M GT.

My question is, which one of 1) and 2) would take precedence? Sufficient/better to have only one of them?
This is just for understanding the mechanism - things work perfectly for me anyway.

As far as I know, it only reads the Preboot com.apple.Boot.plist; the other one seems to be ignored on APFS. However, it is used on HFS+, which doesn't have a Preboot volume.

The flags from NVRAM boot-args and the plist are combined. Neither takes precedence. I think the plist is a better method though, since resetting NVRAM won't mess anything up.

Disabling just Library Validation with the plist is different from disabling the entirety of AMFI with the boot argument. The latter seems to break permissions dialogs, requiring the use of tccplus as you've said. The former does not, so it's preferred. There is also an unofficial kext to disable Library Validation, but it breaks Music for some reason.

And you didn't ask about this, but SIP can be disabled in three ways also: csrutil in recovery mode (which writes an NVRAM key), modifying boot.efi, or SIPManager.kext which currently doesn't work correctly. The patcher(s) used to use the kext, but now the patched boot.efi is used. Again the NVRAM key is avoided since a reset could cause a non-bootable system.

Hope that clears some things up!

 

[hvds]

As far as I know, it only reads the Preboot com.apple.Boot.plist; the other one seems to be ignored on APFS. However, it is used on HFS+, which doesn't have a Preboot volume.

The flags from NVRAM boot-args and the plist are combined. Neither takes precedence. I think the plist is a better method though, since resetting NVRAM won't mess anything up.

Disabling just Library Validation with the plist is different from disabling the entirety of AMFI with the boot argument. The latter seems to break permissions dialogs, requiring the use of tccplus as you've said. The former does not, so it's preferred. There is also an unofficial kext to disable Library Validation, but it breaks Music for some reason.

And you didn't ask about this, but SIP can be disabled in three ways also: csrutil in recovery mode (which writes an NVRAM key), modifying boot.efi, or SIPManager.kext which currently doesn't work correctly. The patcher(s) used to use the kext, but now the patched boot.efi is used. Again the NVRAM key is avoided since a reset could cause a non-bootable system.

Hope that clears some things up!

Many thanks ASentientBot, for this complete picture of the settings of relevance to this thread.

Apple probably rightly assumes that users of supported machines don't use such features apart from quite special cases, and thus there won't be much official information about it. Good that you have put it together for us!

 

[jackluke]

Hello everyone, I just updated the USBOpenCoreAPFSloader, even if previous version still works, this is based on the latest opencore binaries (current version 0.5.9) , that added a new function BlacklistAppleUpdate to block the apple EFI firmware update, as I call it the "big apple logo with big loading bar" (example picture attached), so using this version should allow spoofing to a supported Catalina Mac and using a stock Catalina installer to install it on an unsupported Mac without any unwanted EFI SMC firmware update.

This function should block or ignore this file after a stock macOS Catalina stage1 installer:
/EFI/APPLE/EXTENSIONS/Firmware.scap

hence allowing directly the stage2 installer without any Distribution or OSInstall.mpkg manual patching.

This USBOpenCoreAPFSloader3 version can be also installed near a macOS installer or a macOS installation either internal and usb external.

Of course the configuration includes @parrotgeek1 LegacyUSBInjector.kext (to detect any legacy USB input and output devices) and @Syncretic telemetrap.kext (to block the telemetry.plugin for Core2Duo kp) , and it still allow to detect from non-APFS machine any APFS bootable volumes, mainly the "macOS Installer" stage2 installer example for OTA updates or install directly from macOS desktop, and allow to boot any stock APFS recovery.

Currently by choice the config file that I aligned and updated to version 0.5.9 doesn't spoof to a supported machine, but it can easily been done editing the /EFI/OC/config.plist example this way:

Spoiler

<key>PlatformInfo</key>
<dict>
<key>Automatic</key>
<true/>
<key>UpdateDataHub</key>
<false/>
<key>UpdateNVRAM</key>
<false/>
<key>UpdateSMBIOS</key>
<true/>
<key>UpdateSMBIOSMode</key>
<string>Create</string>
<key>Generic</key>
<dict>
<key>SystemProductName</key>
<string>iMac14,2</string>
<key>SystemSerialNumber</key>
<string></string>
</dict>
<key>DataHub</key>
<dict/>
<key>PlatformNVRAM</key>
<dict/>
<key>SMBIOS</key>
<dict/>
</dict>

In few words from my config.plist you should set simply in the <key>PlatformInfo</key> :

<key>Automatic</key>
<true/>


<key>UpdateSMBIOS</key>
<true/>


<key>Generic</key>
<dict>
<key>SystemProductName</key>
<string>iMac14,2</string>
<key>SystemSerialNumber</key>
<string></string>
</dict>

using an empty serial number takes your current machine serial number
is also possible to spoof instead of the SystemProductName this

<dict>
<key>BoardProduct</key>
<string>Mac-27ADBB7B4CEE8E61</string>
</dict>

but the result is the same

On another opencore thread I made earlier many tests and I can confirm that a Penryn Core2Duo can be spoofed to Haswell, Broadwell, Coffee Lake and KabyLake architecture (spoofing Ivy Bridge Catalina booting worked but with no responsive usb input output devices).

These are some example spoofing Catalina supported machine that worked for MacBook7,1:

Haswell iMac14,2 spoofed board-id output: Mac-27ADBB7B4CEE8E61
Broadwell MacBookAir7,1 (the 11" inch early 2015 version) spoofed board-id output: Mac-9F18E312C5C2BF0B
KabyLake MacBook10,1 (the retina 12" inch version) spoofed board-id output: Mac-EE2EBD4B90B839A8
CoffeeLake iMac19,1 (the retina 5k ddr4 ram 2019 version) spoofed board-id output: Mac-AA95B1DDAB278B95
Macmini7,1 late 2014 (Haswell not Ivy Bridge) spoofed board-id output: Mac-35C5E08120C7EEAF
MacBookPro11,1 (Haswell Retina display) spoofed board-id output: Mac-189A3D4F975D5FFC


Here to download: USBOpenCoreAPFSloader3.app.zip

edit:
There is also an experimental opencore GUI style apple boot manager that can be enabled, mount your external USB EFI volume and in this path /EFI/OC/Drivers/OpenCanopy.efi rename the file to OpenCanopy2.efi

but in my customized setup I preferred to use instead the classic opencore text menu.

edit2:
the funny thing of spoofing (through opencore) to a supported Catalina Mac is that (apart OTA updates automatically detected without catalinaotaswufix patches) NightShift worked using the stock CoreBrightness and stock MonitorPanels frameworks, example picture attached where I spoofed a MacBook7,1 as iMac19,1 .

In "About this Mac" the MacBook is still detected because I used my own serial number while apple populates that window using the machine serial number, but on system profiler can notice that the machine is correctly spoofed as supported catalina Mac (on another picture spoofing as Macmini7,1 can notice that board-id is also spoofed).

 

[TimothyR734]

Hello everyone, I just updated the USBOpenCoreAPFSloader, even if previous version still works, this is based on the latest opencore binaries (current version 0.5.9) , that added a new function BlacklistAppleUpdate to block the apple EFI firmware update, as I call it the "big apple logo with big loading bar", so using this version should allow spoofing to a supported Catalina Mac and using a stock Catalina installer to install it on an unsupported Mac without any unwanted EFI SMC firmware update.

This function should block or ignore this file after a stock macOS Catalina stage1 installer:
/EFI/APPLE/EXTENSIONS/Firmware.scap

hence allowing directly the stage2 installer without any Distribution or OSInstall.mpkg manual patching.

This USBOpenCoreAPFSloader3 version can be also installed near a macOS installer or a macOS installation either internal and usb external.

Of course the configuration includes @parrotgeek1 LegacyUSBInjector.kext (to detect any Legacy USB input and output devices) and @Syncretic telemetrap.kext (to block the telemetry.plugin for Core2Duo kp) , and it still allow to detect from non-APFS machine any APFS bootable volumes, mainly the "macOS Installer" stage2 installer example for OTA updates or install directly from macOS desktop, and allow to boot any stock APFS recovery.

@0403979 , currently by choice the config file that I aligned and updated to version 0.5.9 doesn't spoof to a supported machine, but it can easily been done editing the /EFI/OC/config.plist example this way:


<dict>
<key>SystemProductName</key>
<string>iMac14,2</string>
<key>SystemSerialNumber</key>
<string></string>
</dict>

<key>UpdateSMBIOS</key>
<true/>


On another opencore thread I made many tests and I can confirm that a Penryn Core2Duo can be spoofed to Haswell, Broadwell, Coffee Lake and KabyLake architecture (spoofing Ivy Bridge Catalina booting worked but with no responsive usb input output devices).

These are some example spoofing Catalina supported machine that worked for MacBook7,1:

Spoiler

Haswell iMac14,2 spoofed board-id output: Mac-27ADBB7B4CEE8E61
Broadwell MacBookAir7,1 (the 11" inch early 2015 version) spoofed board-id output: Mac-9F18E312C5C2BF0B
KabyLake MacBook10,1 (the retina 12" inch version) spoofed board-id output: Mac-EE2EBD4B90B839A8
CoffeeLake iMac19,1 (the retina 5k ddr4 ram 2019 version) spoofed board-id output: Mac-AA95B1DDAB278B95
Macmini7,1 late 2014 (Haswell not Ivy Bridge) spoofed board-id output: Mac-35C5E08120C7EEAF
MacBookPro11,1 (Haswell Retina display) spoofed board-id output: Mac-189A3D4F975D5FFC

Here to download: USBOpenCoreAPFSloader3.app.zip

Thank you

 

[simkard]

Dear All,

I'm trying to install Catalina 10.15.3 with latest DosDude patcher 1.4.4.
I manage to successfully create the USB boot media.

While booting on the USB media (using ALT key and selecting the USB install media), it starts well, then all of a sudden, nothing happens and the mac just rise the loading progress bar from approx. 60% to 100% very slowly doing pretty much nothing.

I managed to boot the USB install media using OPTION + V (for verbose mode), and it fails with the attached screenshots, looping ever and ever ...

I tried :

1. Using APFS / MBR / GUID before creating the install media (but I don't think it changes anything at all)
2. Disabling SIP (booting with OPTION + R)
3. Changing DMG initial media to other variants 10.15 / 10.15.3
4. Resetting NVRAM/PRAM

Can someone please help me on that one ?


Thanks

 

[dosdude1]

Dear All,

I'm trying to install Catalina 10.15.3 with latest DosDude patcher 1.4.4.
I manage to successfully create the USB boot media.

While booting on the USB media (using ALT key and selecting the USB install media), it starts well, then all of a sudden, nothing happens and the mac just rise the loading progress bar from approx. 60% to 100% very slowly doing pretty much nothing.

I managed to boot the USB install media using OPTION + V (for verbose mode), and it fails with the attached screenshots, looping ever and ever ...

I tried :

1. Using APFS / MBR / GUID before creating the install media (but I don't think it changes anything at all)
2. Disabling SIP (booting with OPTION + R)
3. Changing DMG initial media to other variants 10.15 / 10.15.3
4. Resetting NVRAM/PRAM

Can someone please help me on that one ?


Thanks

You need to use an older Catalina Patcher version for 10.15.3. Use version 1.3.4.

 

[simkard]

You need to use an older Catalina Patcher version for 10.15.3. Use version 1.3.4.

Thanks for your prompt answer, it is greatly appreciated, moreover, when it's you the dev. thumbs up for that !

I'll try in the upcoming minutes and report back if everything went fine.

 

[simkard]

@dosdude1 : Seems like even with v1.3.4 it ends with same errors ; please see attached screenshots.

ERRATUM : I rebuilt the install media using the 10.15.3 DMG and it loaded fine.
Actually it installed macOS but at the end of SETUP, seems like it restarted a little bit earlier than expected.
But ... it actually rebooted and arrived in Catalina ; YEEEEEAAAAAAAH !

Thanks for your precious help on that one !

 

[simkard]

Now that I've got things sorted out, is there any way to upgrade from 10.15.3 to latest Catalina (10.15.4 or 10.15.5) ?

 

[TimothyR734]

@dosdude1 : Seems like even with v1.3.4 it ends with same errors ; please see attached screenshots.

Thanks for your precious help.

With the Catalina Patcher 1.4.4 you can download 10.15.5 and either create a patcher to install from a usb installer or you can use install to this machine option

 

[dosdude1]

Now that I've got things sorted out, is there any way to upgrade from 10.15.3 to latest Catalina (10.15.4 or 10.15.5) ?

If I knew you wanted to update, I would have said just use the latest Patcher to download and use the latest 10.15.5 installer...

 

[simkard]

With the Catalina Patcher 1.4.4 you can download 10.15.5 and either create a patcher to install from a usb installer or you can use install to this machine option

I will not be able to boot up from USB as I previously stated, anyway, maybe the in-OS update might work, I'll try and report back here.

See you in a few minutes/hours, wish me "good luck" ?
[automerge]1591894940[/automerge]

If I knew you wanted to update, I would have said just use the latest Patcher to download and use the latest 10.15.5 installer...

It didn't work using v1.4.4 patcher and downloaded copy of Catalina 10.15.5.
I'm going to try in-OS update ... do you think it will go fine/wrong ? ?

 

[MacGero]

I will not be able to boot up from USB as I previously stated, anyway, maybe the in-OS update might work, I'll try and report back here.

See you in a few minutes/hours, wish me "good luck" ?
[automerge]1591894940[/automerge]


It didn't work using v1.4.4 patcher and downloaded copy of Catalina 10.15.5.
I'm going to try in-OS update ... do you think it will go fine/wrong ? ?

The same problem I've got. sticking on 10.15.3 and can't update to 10.15.4 or 5 with the patcher 1.4.4
It's booting from external HDD and the Mac is black... nothing happens at all ...

Very frustrating

 

[simkard]

Ok so I can report that going from v1.3.4 patcher and 10.15.3 >>> TO >>> v1.4.4 patcher with latest 10.15.5 went fine.
For those of you who had the same problem than me and that MacBookPro8,1 ... this is the method !

Cheers to eveyrone that helped me !

 

[hvds]

Thank you

Thank you jackluke - used your new USBOpenCoreAPFSloader3.app to make a new OpenCore loader next to a bootable USB installer for 10.15.5.
Repeated OTA installation of 10.15.6DB2 to a USB SSD to test it - CatalinaOTAswufix.app first, then used the new OpenCore loader to boot into the macOS Installer for OTA phase2 (as required for my mid 2009 MBP5,2 to get LegacyUSB into place).

All fine as usual!

(Booting with the new OpenCore loader now starts with a white-on-black screen, and boot menu is indico.)

EDIT: just read your edit2 about the nice effects of spoofing. Interesting...

 

[jackluke]

Thank you jackluke - used your new USBOpenCoreAPFSloader3.app to make a new OpenCore loader next to a bootable USB installer for 10.15.5.
Repeated OTA installation of 10.15.6DB2 to a USB SSD to test it - CatalinaOTAswufix.app first, then used the new OpenCore loader to boot into the macOS Installer for OTA phase2 (as required for my mid 2009 MBP5,2 to get LegacyUSB into place).

All fine as usual!

(Booting with the new OpenCore loader now starts with a white-on-black screen, and boot menu is indico.)

EDIT: just read your edit2 about the nice effects of spoofing. Interesting...

The version uploaded doesn't spoof any supported machine, you should edit manually the config.plist (just setting few xml keys as explained in my previous post), but for now that feature is not really required, sometimes after an opencore setup update I change the menu text color, you can customize it also as you want, I wrote a little guide simplifying that on opencore manual: Opencore menu text color customize

only menu difference instead of <key>PickerAttributes</key> from opencore 0.5.9 the developers changed the xml key in <key>ConsoleAttributes</key>

To easily detect and access the hidden EFI volumes you can use this @ASentientBot utility:

macOS 10.15 Catalina on Unsupported Macs

Not sure how useful this will be, but I made a little thing to show all volumes in Disk Utility, including ones that are usually hidden, like Preboot or EFI. (This used to be possible via a defaults command on the pre- El Capitan version of Disk Utility, but not since.) If you want to try it...

forums.macrumors.com

 

[jettie1767]

If I knew you wanted to update, I would have said just use the latest Patcher to download and use the latest 10.15.5 installer...

Dosdude1, if I have prepared the usb stick using your latest patcher and lates Catalina build 10.15.6. I already am on 10.15.5. If I use the image in the usb stick, will it wipe out everything on the Mac again just to get it upgraded to 10.15.6?

 

[TimothyR734]

Dosdude1, if I have prepared the usb stick using your latest patcher and lates Catalina build 10.15.6. I already am on 10.15.5. If I use the image in the usb stick, will it wipe out everything on the Mac again just to get it upgraded to 10.15.6?

The Catalina Patcher only downloads point releases .4 .5 etc and Supplemental updates never beta as 10.15.6 is still in beta production

 

[Ryn89]

Hello,

For the past few days I have been trying to use the Catalina Patcher v1.4.4 with my MacBook Air mid-2011 4,2 (High Sierra 10.13.6) to upgrade to Catalina v10.15.5

I have been using the recommended method of creating a bootable installer on a USB (Which is formatted with GUID partition and Mac OS Extended (journaled). The patcher completes successfully in creating this bootable installer USB.

When I then shutdown and power on (holding the 'option' key) and select the USB to boot from, it goes ahead fine until about 2/3rds of the way through where it gives me the prohibited symbol.

So far I have:

• Re-downloaded Catalina (the first time it had gotten interrupted, so I thought this might have corrupted a file somewhere, but the second time had no such issue so I can assume there is no corruption in the catalina installer)
• checked that my BootROM is up to date (there was an update to High Sierra recently, but this hasn't changed anything) (it is 135.0.0.0.0 which as far as I can tell is the most recent for my Air 4,2)
• Checked the permissions for the USB and made it 'read&write' for everyone, which has been suggested as a potential issue stopping installation. I've also tried unticking the 'ignore ownership'

I have a feeling it might be something to do with the USB, as when I check info in Disk Utility after making it into a bootable drive, it says 'no' for both the 'journaled' and 'bootable' sections. When I experimentally tried making a bootable drive for Catalina through another app, these sections said 'yes' for both (though obviously trying to boot off this gives me an immediate prohibited symbol since this is an unsupported macbook).

Or perhaps I need to manually disable SIP? Though I saw a tweet from dosdude1 saying the patcher automatically disables it for you (I assume only when booting from a USB), but it is something I haven't tried yet.

Does anyone have any ideas or am I missing something truly obvious? I couldn't find anyone else having issues with the 'prohibited' symbol and this patcher.

 

[Ryn89]

Hello,

For the past few days I have been trying to use the Catalina Patcher v1.4.4 with my MacBook Air mid-2011 4,2 (High Sierra 10.13.6) to upgrade to Catalina v10.15.5

I have been using the recommended method of creating a bootable installer on a USB (Which is formatted with GUID partition and Mac OS Extended (journaled). The patcher completes successfully in creating this bootable installer USB.

When I then shutdown and power on (holding the 'option' key) and select the USB to boot from, it goes ahead fine until about 2/3rds of the way through where it gives me the prohibited symbol.

So far I have:

• Re-downloaded Catalina (the first time it had gotten interrupted, so I thought this might have corrupted a file somewhere, but the second time had no such issue so I can assume there is no corruption in the catalina installer)
• checked that my BootROM is up to date (there was an update to High Sierra recently, but this hasn't changed anything) (it is 135.0.0.0.0 which as far as I can tell is the most recent for my Air 4,2)
• Checked the permissions for the USB and made it 'read&write' for everyone, which has been suggested as a potential issue stopping installation. I've also tried unticking the 'ignore ownership'

I have a feeling it might be something to do with the USB, as when I check info in Disk Utility after making it into a bootable drive, it says 'no' for both the 'journaled' and 'bootable' sections. When I experimentally tried making a bootable drive for Catalina through another app, these sections said 'yes' for both (though obviously trying to boot off this gives me an immediate prohibited symbol since this is an unsupported macbook).

Or perhaps I need to manually disable SIP? Though I saw a tweet from dosdude1 saying the patcher automatically disables it for you (I assume only when booting from a USB), but it is something I haven't tried yet.

Does anyone have any ideas or am I missing something truly obvious? I couldn't find anyone else having issues with the 'prohibited' symbol and this patcher.

All good, my persistence with the issue has paid off.

For anyone else who does come across this, it is probably the USB you are using.
I tried with a 32GB Verbatim (2.0) the first time, and it was refusing to work.
Now I have swapped to a SanDisk Cruzer (32gb, 2.0) and it is finally looking like it will work! No more prohibited sign!
The first time I rebooted while holding 'option' - the name that came up for my USB was not what I had called it. So I restarted and went to 'get info' for the USB, changed permissions for all to read & write, and unticked the box at the bottom left for 'ignore ownership'. When I restarted into boot option mode, the USB came up with what I had named it.

Hope that helps anyone in the future that has a similar issue.

 

[quaccOS]

Anyone know where I could find a full macOS Catalina Installer App 10.15.0/1/2? The 10.15.3 Safari Extensions bug is still present on my MBP 7,1 so I'd like to downgrade, tick the Safari ad-blocker boxes – and return to 10.15.5.

https://rime.im and https://www.google.co.jp/ime are usable for Chinese and Japanese inputs respectively, but I still miss the fluidity of the native macOS input sources. Patched Catalina is still plagued by several random bugs that outweigh the benefits of having the newest version of macOS, e.g. no Software Updates, no AirDrop, no All Photos tab, no working Chinese/Japanese IME, Launchpad unexpectedly re-ordered, certain apps not working unless you either patch it or download an older version (Zoom, iMovie etc).

I was hoping to buy the new 2020 16" MBP, since I still have the 2010 13" MBP – but if it doesn't release, I was going to buy a secondhand 2015 15" MBP (IG), but they're such a rare model! – and way too overpriced because the Butterfly key mechanisms were a fragile joke. There were rumours of mini-LED MBP displays for Q4 2020, but it's presumably delayed until 2021 due to the pandemic disrupting supply chains. And also, the transitioning from Intel to ARM CPUs…which I guess would end Bootcamp. Disappointing, as it was great for gaming

 

[TimothyR734]

Anyone know where I could find a full macOS Catalina Installer App 10.15.0/1/2? The 10.15.3 Safari Extensions bug is still present on my MBP 7,1 so I'd like to downgrade, tick the Safari ad-blocker boxes – and return to 10.15.5.

https://rime.im and https://www.google.co.jp/ime are usable for Chinese and Japanese inputs respectively, but I still miss the fluidity of the native macOS input sources. Patched Catalina is still plagued by several random bugs that outweigh the benefits of having the newest version of macOS, e.g. no Software Updates, no AirDrop, no All Photos tab, no working Chinese/Japanese IME, Launchpad unexpectedly re-ordered, certain apps not working unless you either patch it or download an older version (Zoom, iMovie etc).

I was hoping to buy the new 2020 16" MBP, since I still have the 2010 13" MBP – but if it doesn't release, I was going to buy a secondhand 2015 15" MBP (IG), but they're such a rare model! – and way too overpriced because the Butterfly key mechanisms were a fragile joke. There were rumours of mini-LED MBP displays for Q4 2020, but it's presumably delayed until 2021 due to the pandemic disrupting supply chains. And also, the transitioning from Intel to ARM CPUs…which I guess would end Bootcamp. Disappointing, as it was great for gaming

Which version of Catalina are you currently using? The Catalina Patcher downloads 10.15.5 Supplemental update. For Photo's you could create a smart album rename it Photo's that is a work around. iMovie and Zoom require metal but the older version of iMovie and patching Zoom works and I am sure more apps will need patched in 10.16