Below you will find an extensive list of the work that went into MorphOS 3.9.
Please note that this is just an overview and does not mention or explain every new feature.
 
MorphOS 3.9 boot.img Changes

The following is a (probably incomplete) list of changes made between the 3.8 and 3.9 release of MorphOS to the ROM (boot.img) based components.

FatFS

  • Fixed access to objects which are stored in first entry in root directory

hid.class

  • Fixed setup of some keyboards which refused to initialize properly (e.g. Rapoo E9050)

Quark

  • Properly detect and add the AGP bridge on PowerMac7,2 machines
  • Disabled unconditional debug on Pegasos 2 machines
MorphOS 3.9 Disk Changes

Following is a (probably incomplete) list of changes made to the disk based components of MorphOS.

Applications/Flacapella

  • Fixed a crash when dropping a CD icon onto the application window

Applications/Odyssey

  • Updated to OpenSSL 1.0.1o

Applications/RemoteShell

  • Updated to OpenSSL 1.0.1o

Applications/Scribble

  • Improved handling of a number of file types that were only partly supported.

MorphOS/Classes/Datatypes/bmp.datatype

  • Now properly loads BMP-files where lines are stored from top to bottom

MorphOS/Classes/Multimedia/ms-adpcm.decoder

  • Fixed problem with stream rewind.

MorphOS/Devs/Monitors/Radeon

  • Fixed a stability problem when using an R300 chip or newer with certain Powermac machines
  • Added support for the AGP bridge found on PowerMac7,2 machines
  • Disabled unconditional debug for RadeonHD cards

MorphOS/Devs/Networks/802.11/Atheros5000

  • Fixed the handling of non-standard WiFi data frames (e.g. AVM´s WDS frames)

MorphOS/Devs/Networks/802.11/B43

  • Fixed the handling of non-standard WiFi data frames (e.g. AVM´s WDS frames)

MorphOS/Libs/thumbnail.library

  • Fixed a problem that could cause very large pictures to not load

MorphOS/Libs/tinygl.ibrary

  • Fixed a problem where enabling the normal array before setting any data for it could cause spurious debug output or crashes

MorphOS/Libs/TinyGL/r200.library

  • Fixed an issue when using compressed textures with a width of 32 pixels or less

MorphOS/Libs/TinyGL/r300.library

  • Fixed an issue when using compressed textures with a width of 32 pixels or less
  • Worked around a hardware bug where combining compressed textures and regular textures with multitexturing would cause graphics corruptions
  • As a result of the work around above, some applications might show slightly increased performance

MorphOS/Locale/Countries

  • Fixed first day of week for some countries

MorphOS/MUI

  • Fixed image rendering for tiled external images with alpha channel

MorphOS/Prefs/Laptop.mprefs

  • Enabled keyboard backlight timeout setting for PBook5,2/5,3/5,4/5,5 as well

OpenSSL

  • Fixed a security issue where an attacker could downgrade certain connections to use weaker security, as described in CVE-2015-4000
  • Updated to OpenSSL 1.0.1o