ISL Light 5.0.2551.35 and Universal Add-On 5.0.2551.35 for ISL Light for Android (2026-08-05)
General Information
On 5th of August the following was released:
- ISL Light 5.0.2551.35 for Android (release_date=2026-07-21, build=a5468d48d6ad436d913a0d2724007261d9ff3561, platform=Android, os_version=9.0.0-FFF).
- Universal Add-On 5.0.2551.35 for ISL Light for Android (release_date=2026-07-21, build=ab8b9ffd31c83120ec421b5004c219c5d2199e73, platform=Android, os_version=9.0.0-FFF).
Upgrading to new version
Hosted service users please check Upgrading Hosted Service for iOS or Android .
Server license users please check Upgrading Server License for iOS or Android .
ISL Light 5.0.2551.35 for Android is available in Google Play Store and it has also a corresponding program file (isl_light_5_0_2551_35_android_202607210845_87185282.program) which adds information about customizations to ISL Conference Proxy. Server License users need to use Online update to get the file.
Universal Add-On 5.0.2551.35 for ISL Light for Android is available in Google Play Store.
Improvements
Description
TargetSDK of the ISL Light application was raised to version 35.
Description
The video plugin used in ISL Light was using yuv2rgb.neo.S library which was now replaced with libyuv library.
Description
Added support for file transfer in ISL Light on Android. There is no file manager UI on Android device; instead the remote user (operator) requests file access and the Android user receives a confirmation prompt.
Once confirmed, the user has to grant permission in system settings (on Android 11 and newer) or through a system dialog (on Android 6-10).
By default, the root of external storage is shown in the file manager. Files can be transferred in both directions, renamed, deleted, and new folders can be created. When file access is granted, a Revoke File Access option appears in the menu.
Description
LZMADecode was removed from hefa-rpt and XZ is now included as a default in all builds of hefa-rpt.
Description
Added support for 16 KB page size on Mobile Android.
Description
Options "ssl_protocol" and "ssl_ciphers" were added to AutoTransport. Besides legacy OpenSSL format, the options support numeric hex codes:
- ssl_protocol: "0x0301-0x10000" for TLS 1.0 profile and "0x0303-0x10000" for TLS 1.2 profile. 3-byte hex code "0x10000" is interpreted as no bound.
- ssl_ciphers: can now be specified using a simple numeric hex code list: "0x1302 0x1301 ..."
Description
The log line of ISL Light now includes ecdh_ctx log key which shows which algorithm was used to establish the shared secret.
Description
ISSC ZRLE codec was rewritten. The new implementation is simpler, clearer and allows further enhancements. This new implementation also improves performance of desktop sharing.
Description
Updated default ISL Light logo.
Description
Added support for MDM (Mobile Device Management) deployment of ISL Light on Android. Administrators can now provide command lines via MDM configuration to pre-configure remote access, including granting connections. Command lines are read from links and are executed at app launch, and only re-applied if the configuration changes. A new "Reset Deployment" option was added in Remote Access settings to force re-applying the MDM configuration.
Description
Session codes in ISL Light on Android are now automatically formatted with a space every 3 digits as the user types, both when entering a session code to join and when displaying support session codes. This makes long codes easier to read and type.
Description
In certain cases desktop streaming stopped working. The operator log showed an issue with JPEG decoding due to incorrect JPEG encoding on the streaming side of the sent screen update which caused the streaming to stop. Libjpeg turbo was updated to version 3.1.0 and the issue with JPEG decoding was resolved.
The defect was fixed.
Description
The range of enum values was expanded when loading metrics from shared section. This resolves an issue with user action metrics, where ZRLE metrics from issc_stream (external process) were not seen in the main application. Additionally a crash was fixed when dumping single UMA metric that has all buckets non-zero.
The defect was fixed.
Description
Users experienced an issue where the Enter key was not supported when controlling an Android device via the Universal Addon. The functionality was redesigned and the Enter key is now handled correctly.
The defect was fixed.
Description
Users experienced an issue where they were unable to open the downloaded files from ISL AlwaysOn File Sharing directory in ISL Light. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed,
Description
Users in previous versions experienced an issue where call notification was not shown when call was started by the operator when ISL Light was minimized. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where they were prompted to install Universal Addon on Zebra devices even though it is not supported on such devices. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where remote control was not instantly available in session when user activated Universal Addon. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where setting "Session timeout" did not work correctly on android devices. The setting was removed.
The defect was fixed.
Description
Users experienced an issue with broken GUI in ISL Light on Android 15 devices. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where message box inside session was closed when user reconnected to the session. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue when they were showing their screen on Pixel 9 device, locked and unlocked screen the ISL Light application would stop sharing the screen. Functionality was redesigned and the issue is not reproducible.
The defect was fixed.
Description
Users experienced an issue where ISL Light application would crash on Android devices if the application was minimized for too long. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users sometimes experienced a crash of ISL Light application on android devices when operator and client performed action at the same time. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where the ISL Light application would never stop searching for server if user entered incorrect server in the settings. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
ISL Light Android application was using old crash implementation to report crash reports. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where ISL Light application would crash on the android devices if ISL AlwaysOn module was not installed on the ISL Conference Proxy. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where ISL Light application would crash on Android devices when user would open ISL Light settings. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users on devices running Android 14 or Android 15 had to enable camera permission for ISL Light in order to start a session. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where there was a hidden clickable text box in a call view in ISL Light for Android. The functionality was redesigned and the issue is no longer reproducile.
The defect was fixed.
Description
Users experienced an issue where ISL Light would shop working if camera or microphone permissions were changed while user was in a remote session. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where the instructions dialog was not shown fully. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
MbedTLS cipher suite used was simplified to be similar to server OpenSSL cipher suite. Additionally the following ciphers were removed:
- DHE
- ECDH
- CAMELLIA
- 3DES (except TLS-RSA-WITH-3DES-EDE-CBC-SHA)
Description
Two options were added to AutoTransport which affect wininet-http and wininet-https transports:
- http_proxy_bypass: configure which hostnames should (or not) use direct connection without proxy, use <-loopback> to allow localhost connections through proxy
- http_proxy_force_auth: immediately start with configured user+password when connecting, used to resolve a problem when Windows system account is not allowed to connect through proxy but http_proxy_user is allowed and proxy is using Windows integrated authentication
Description
Users experienced an issue where ISL Light application would crash on Android when a call was initiated from remote side. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where desk and client chat messages were switched in ISL Light session on android device. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where they were unable to view unattended computers screen again after they were connected to the computer and stopped watching remote screen. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where audio call did not work in session if camera permissions were disabled. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where they were unable to connect to the unattended mobile device after the device was added to the list of unattended devices. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where they were unable to connect to unattended computer from an android device. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where they were unable to accept or deny a call in ISL Light session when joining a session after ISL Light closed. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where the microphone in video call would automatically turn on after switching from ISL Light to different application and back to ISL Light. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where loading spinner was still being shown after closing ISL AlwaysOn session from an android device. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where some strings were not translated when user reached maximum number of licensed connections. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where microphone and camera in a call were both turned off on ISL Light Android when operator turned off the microphone of the client. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where a call from ISL Light Desk would be cancelled when connected to an android device. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where they were unable to view Android devices screen when connecting from a windows machine. Functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue when connected from Android 15 or newer devices where the whole screen was not visible when keyboard was opened. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where remote system information for Android 16 devices returned empty parameters. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced a crash of ISL Light on Android when connecting to an unattended Android device after a reboot, before the local user had opened the ISL Light app. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
Description
Users experienced an issue where ISL Light crashed on Android when connecting to a remote computer and the password prompt dialog was shown. The functionality was redesigned and the issue is no longer reproducible.
The defect was fixed.
