Since a commit from 20 days ago that fixes deprecation warnings, the JUCE Demo as well as our own JUCE-based apps crash upon opening on macOS 10.8.5.
Relevant info:
Crashed Thread: 0 JUCE Message Thread Dispatch queue: com.apple.main-thread
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Application Specific Information:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSWindowGraphicsContext CGContext]: unrecognized selector sent to instance 0x7fc75a4eb380'
terminate called throwing an exception
abort() called
Application Specific Backtrace 1:
0 CoreFoundation 0x00007fff8c05eb06 __exceptionPreprocess + 198
1 libobjc.A.dylib 0x00007fff851873f0 objc_exception_throw + 43
2 CoreFoundation 0x00007fff8c0f540a -[NSObject(NSObject) doesNotRecognizeSelector:] + 186
3 CoreFoundation 0x00007fff8c04d02e ___forwarding___ + 414
4 CoreFoundation 0x00007fff8c04ce18 _CF_forwarding_prep_0 + 232
5 DemoRunner 0x000000010360f235 _ZN4juce19NSViewComponentPeer8drawRectE6CGRect + 117
6 DemoRunner 0x000000010360cef2 _ZN4juce15JuceNSViewClass8drawRectEP11objc_objectP13objc_selector6CGRect + 130
7 AppKit 0x00007fff8dc43064 -[NSView _drawRect:clip:] + 4217
8 AppKit 0x00007fff8dc416c1 -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] + 1656
9 AppKit 0x00007fff8dc41ad9 -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] + 2704
10 AppKit 0x00007fff8dc3f6f2 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 817
11 AppKit 0x00007fff8dc3f143 -[NSThemeFrame _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 314
12 AppKit 0x00007fff8dc3ad6d -[NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:] + 4675
13 AppKit 0x00007fff8dc04c93 -[NSView displayIfNeeded] + 1830
14 AppKit 0x00007fff8dcc1a18 -[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 1377
15 AppKit 0x00007fff8dcc1038 -[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 940
16 AppKit 0x00007fff8dcc0c1f -[NSWindow orderWindow:relativeTo:] + 159
17 AppKit 0x00007fff8dcb96dc -[NSWindow makeKeyAndOrderFront:] + 48
18 DemoRunner 0x0000000103618ba1 _ZN4juce19NSViewComponentPeer7toFrontEb + 209
19 DemoRunner 0x000000010349804a _ZN4juce9Component7toFrontEb + 218
20 DemoRunner 0x000000010356a64f _ZN4juce14TopLevelWindow17visibilityChangedEv + 111
21 DemoRunner 0x000000010356a5cf _ZN4juce15ResizableWindow17visibilityChangedEv + 31
22 DemoRunner 0x0000000103496a24 _ZN4juce9Component27sendVisibilityChangeMessageEv + 52
23 DemoRunner 0x00000001034966a8 _ZN4juce9Component10setVisibleEb + 520
24 DemoRunner 0x0000000102dbcd1e _ZN21DemoRunnerApplication13MainAppWindowC2ERKN4juce6StringE + 526
25 DemoRunner 0x0000000102dbcafd _ZN21DemoRunnerApplication13MainAppWindowC1ERKN4juce6StringE + 29
26 DemoRunner 0x0000000102dbc561 _ZN21DemoRunnerApplication10initialiseERKN4juce6StringE + 145
27 DemoRunner 0x0000000103376ed9 _ZN4juce19JUCEApplicationBase13initialiseAppEv + 201
28 DemoRunner 0x00000001035724e5 _ZN4juce15JUCEApplication13initialiseAppEv + 21
29 DemoRunner 0x0000000103376c4d _ZN4juce19JUCEApplicationBase4mainEv + 301
30 DemoRunner 0x0000000103376abc _ZN4juce19JUCEApplicationBase4mainEiPPKc + 60
31 DemoRunner 0x0000000102dbc373 main + 51
32 libdyld.dylib 0x00007fff880ab7e1 start + 0
Thread 0 Crashed:: JUCE Message Thread Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x00007fff8654e212 __pthread_kill + 10
1 libsystem_c.dylib 0x00007fff84e94b24 pthread_kill + 90
2 libsystem_c.dylib 0x00007fff84ed8f61 abort + 143
3 libc++abi.dylib 0x00007fff895f79eb abort_message + 257
4 libc++abi.dylib 0x00007fff895f539a default_terminate() + 28
5 libobjc.A.dylib 0x00007fff85187873 _objc_terminate() + 91
6 libc++abi.dylib 0x00007fff895f53c9 safe_handler_caller(void (*)()) + 8
7 libc++abi.dylib 0x00007fff895f5424 std::terminate() + 16
8 libc++abi.dylib 0x00007fff895f658b __cxa_throw + 111
9 libobjc.A.dylib 0x00007fff8518750c objc_exception_throw + 327
10 com.apple.CoreFoundation 0x00007fff8c0f2f49 -[NSException raise] + 9
11 com.apple.AppKit 0x00007fff8dc3b6e8 -[NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:] + 7102
12 com.apple.AppKit 0x00007fff8dc04c93 -[NSView displayIfNeeded] + 1830
13 com.apple.AppKit 0x00007fff8dcc1a18 -[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 1377
14 com.apple.AppKit 0x00007fff8dcc1038 -[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 940
15 com.apple.AppKit 0x00007fff8dcc0c1f -[NSWindow orderWindow:relativeTo:] + 159
16 com.apple.AppKit 0x00007fff8dcb96dc -[NSWindow makeKeyAndOrderFront:] + 48
17 com.juce.demorunner 0x0000000103618ba1 juce::NSViewComponentPeer::toFront(bool) + 209
18 com.juce.demorunner 0x000000010349804a juce::Component::toFront(bool) + 218
19 com.juce.demorunner 0x000000010356a64f juce::TopLevelWindow::visibilityChanged() + 111
20 com.juce.demorunner 0x000000010356a5cf juce::ResizableWindow::visibilityChanged() + 31
21 com.juce.demorunner 0x0000000103496a24 juce::Component::sendVisibilityChangeMessage() + 52
22 com.juce.demorunner 0x00000001034966a8 juce::Component::setVisible(bool) + 520
23 com.juce.demorunner 0x0000000102dbcd1e DemoRunnerApplication::MainAppWindow::MainAppWindow(juce::String const&) + 526
24 com.juce.demorunner 0x0000000102dbcafd DemoRunnerApplication::MainAppWindow::MainAppWindow(juce::String const&) + 29
25 com.juce.demorunner 0x0000000102dbc561 DemoRunnerApplication::initialise(juce::String const&) + 145
26 com.juce.demorunner 0x0000000103376ed9 juce::JUCEApplicationBase::initialiseApp() + 201
27 com.juce.demorunner 0x00000001035724e5 juce::JUCEApplication::initialiseApp() + 21
28 com.juce.demorunner 0x0000000103376c4d juce::JUCEApplicationBase::main() + 301
29 com.juce.demorunner 0x0000000103376abc juce::JUCEApplicationBase::main(int, char const**) + 60
30 com.juce.demorunner 0x0000000102dbc373 main + 51
31 libdyld.dylib 0x00007fff880ab7e1 start + 1
btw looking to the crash this line seems suspect and indeed it is (reverting that specific change solves the issue)
Note: for a JUCE demo to work on 10.8 before that commit remember to set the deployment target to 10.8 (or lower). I built with Xcode 10.2.1 on macOS 10.14.5
In the future I suggest that whenever the JUCE team fixes deprecation warnings be sure to test the changes on older OSs too because deprecation warnings are a trap more often than not.
Otherwise again it’s going to take most of my day to bisect it 
My process was first assuming that the error is mine and bisecting on own project’s repository and then when I found that it’s coming from JUCE I entered a whole new headache because we use our own bug-fix branch (btw in our branch the problem is now fixed in the juce5 and ARA branches) and git bisect doesn’t work well with merges…
Cheers 
Yair