# IMPORTANT - PLEASE READ: TLXOS 5.x has been released, including both a new Long Term Stable version (5.0.0) and a progressive version (5.2.0). TLXOS RPi 5.0.0 LTS does **NOT** support the Raspberry Pi 5 - you must install RPi 5.2.0 for that. You cannot upgrade directly from TLXOS 4.x to 5.x using TMS. You must upgrade via a bridging upgrade that we have named "version 4.99.99" (it isn't really that, it's just a rearrangement of whatever version of TLXOS 4.x you are already using) before attempting a TLXOS 5.x upgrade. You can, of course, choose to reinstall from scratch using a TLXOS 5.x installer / SD card imager instead, which will not require the intermediary 4.99.99 upgrade. If you have a short attention span, you can probably skip the rest (but if that's the case you have probably stopped reading already!). --- ## TLXOS 5.x DESIGN CHANGES TLXOS 5.x differs from TLXOS 4.x in four major respects: 1. It no longer has a dedicated Maintenance Mode disk partition, nor a separate Maintenance Mode kernel. The /boot partition has been enlarged to use all of the space formerly dedicated to the /tfm partition, and Maintenance Mode now takes the form of an alternative easy userspace (/boot/tfm.img), i.e. it uses the same kernel as Normal Mode. This arrangement makes better use of the limited space allocated by TLXOS 4.x, and thereby allows us to provide a TMS-driven upgrade strategy that doesn't require a complete reinstall. 2. Unlike TLXOS 4.x, which had forever-fixed sizes, 5.x is designed to cope with future enlargement of /boot and /actualroot filesystems (within reason - you will still need to have sufficient unallocated and/or reclaimable disk space). For maximum upgrade reliability, we have kept TLXOS 5.0.0 LTS sizes exactly the same as those of TLXOS 4.x. TLXOS 5.2.0, however, is much larger, on account of reversion to an uncompressed ext2 root filesystem (we only switched to compressed Reiser4 in late 4.x as a space-saving desperation measure - uncompressed filesystems are faster to access). The minimum practical disk(/SD card) size for TLXOS 5.2.0 is therefore now 4 GB, although there is an alternative solution for old x86 devices with 2 GB SSDs (see below). 3. Support for 32-bit hardware is now deprecated. Only TLXOS 5.0.x LTS (and possibly its successor LTS release) continue to support Raspberry Pi models earlier than the Pi 3 and very old PCs with 32-bit only CPUs. TLXOS RePC >= 5.2.0 is fully 64-bit, which has eliminated the need for a separate SFF edition, so we have discontinued that after 5.0.0 LTS. TLXOS RPi now has an alternative fully 64-bit variant, which you may want to consider using if you do not need VMware Horizon Client (see below). TLXOS RPi >= 5.2.0 does not support Pi <= 2 despite temporarily having dual 32- and 64-bit kernels (see below). 4. Maintenance Mode now provides better upgrade progress feedback, both in TMS and on the device console. Progress of TMS-initiated upgrades is now shown on the device console, and both TMS and device console now show percentage completion of filesystem write operations, as well as downloads. For other significant differences, please read the 5.0.0 and 5.2.0 Release Notes (https://help.thinlinx.com/knowledgebase.php?article=95 and https://help.thinlinx.com/knowledgebase.php?article=100 respectively). Although we don't have a DIY hotfix capability yet, nor universal licenses, both are coming later in TLXOS 5.x. ## WHAT HAPPENED TO TLXOS 5.1.0? We skipped it. The Debian 11 (Bullseye) release that we were planning to use as the basis for the progressive release of TLXOS 5.x was already obsolete when we started work on 5.x, and because TLXOS 5.x developement and testing dragged on for so long, we had enough time to adequately develop and test a successor release (5.2.0) based on Debian 12 (Bookworm) in parallel. Moreover, Raspberry Pi 5 support was added only to Debian/Raspbian Bookworm, and some of this (e.g. Mesa) could not be backported to Bullseye. We therefore decided to go with Bookworm rather than Bullseye for the progressive TLXOS 5.x release, and keep 5.1.0 in reserve for a future LTS upgrade. 5.0.0 LTS, which is still based on Debian 10 (Buster) might therefore prove to be a somewhat short-lived LTS sequence. Unlike 5.0.0 LTS, the hypothetical 5.1.0 LTS would (mostly) support the Pi 5 and have a larger disk footprint similar to 5.2.0. Please note that unlike mainline Debian/Raspbian Bookworm, TLXOS 5.2.0 continues to use X11, not Wayland, and a 4k page size. ## WHY IS 5.0.0 LTS' KERNEL SO "OLD"? We couldn't use a 6.1 kernel in TLXOS 5.0.0 for two reasons, both of which are related to our goal of minimizing the risk involved in a 4.x to 5.0.0 LTS upgrade by retaining TLXOS 4.x sizing: 1. Reiser4 patches are not available for any kernel later than 5.16, and Reiser4 is needed for compression, without which root filesystems will not fit in the space provided by TLXOS 4.x. 2. More recent kernels such as 6.1 are significantly larger, and would not fit in the combined space provided for /boot and /tfm filesystems in TLXOS 4.x in the RPi and RePC cases. Consequently, we recommend that customers do **not** use 5.0.0 LTS for any PC hardware that has been purchased new in the last 1-2 years, due to the fairly high probability that the 5.0.0's 5.15 kernel does not support certain chipsets in your PC (in particular, Intel Integrated GPUs and WiFi). In future LTS releases (either 5.0.x or 5.1.x), we will cease to match TLXOS 4.x sizing and include a later version kernel. This won't prevent 4.x to 5.x LTS upgrades, but it will result in a higher upgrade failure risk if you are using low capacity storage (<= 4 GB) or very old releases of TLXOS 4.x. ## HOW CAN I SWITCH FROM SFF TO REPC? We're still working on that. TLXOS (more accurately, tms_client) will already accept a SFF license proof token as sufficient to operate RePC - it has done for some time now - but we have not yet made the necessary changes to accept RePC license requests (in the absence of free RePC licences) on our license server. We'll get this done ASAP. In the meantime, you can try installing or upgrading to TLXOS SFF 5.0.0 LTS - this might still be adequate for your hardware. ## RASPBERRY PI 5 SUPPORT PROBLEMS Unfortunately, neither Citrix Workspace App nor VMware Horizon Client officially support the Pi 5, and we've had to make some compromises to get them to work at all. In TLXOS RPi 5.2.0, we had to downgrade Workspace App to version 20.12, because all later versions crash when running under a 64-bit kernel, and there is a known problem whereby Horizon Client (which won't even run on a Pi 5 without an additional workaround we came up with) will crash when using USB redirection under a 64-bit kernel. We had wanted to provide a single 64-bit kernel for TLXOS RPi 5.2.0, but in order to avoid the latter problem wherever possible, we were forced to include a secondary 32-bit kernel for Pi 3s and 4s. For customers who require a later version of Workspace App and are not using Pi 5s (which are incapable of running the 32-bit kernel), we will provide a Workspace App hotfix. Customers who require a later version of Workspace App and have no requirement for Horizon Client can install an alternative fully 64-bit version of TLXOS RPi 5.2.0 that comes with an ARM64 version of Workspace App 23.11 that does not have the crash problem, which only occurs when running 32-bit ARM binaries under a 64-bit ARM kernel. Horizon Client cannot be provided for the 64-bit TLXOS RPi 5.2.0 variant because VMware have not ported Horizon Client to ARM64 yet. TLXOS RPi 5.2.0 and TLXOS RPi64 5.2.0 look like the same thing to TMS, so you can only use TMS to deploy one or the other, not both (downloading 64-bit RPi 5.2.0 will overwrite TMS' copy of 32-bit RPi 5.2.0, and vice versa). Unfortunately at present there is no way to avoid a Horizon Client crash on the Raspberry Pi when a device eligible for USB redirection is present, other than changing "Redirect USB" to "No" in the TMS or TLXconfig GUI. This means that access to client-connected USB storage devices will not be possible, since the ARM port of Horizon Client lacks support for client drive redirection (i.e. USB redirection is the only way to achieve this). Also, the usual ThinLinX boot screen with the progress bar won't display properly on the Pi 5, which has to do with the old version of Plymouth that we are using not properly supporting DRM framebuffers on ARM platforms (and therefore falling back to the text mode tribar), but we didn't regard this as a high priority problem and haven't yet spent much time on trying to fix it. ## USING REPC LIVE TO INSTALL REPC ON A TINY SSD RePC Live now uses a ZISOFS (Linux-specific compressed ISO9660) root filesystem, which achieves even better compression than Reiser4 on account of being read-only. This allows DIY installation of RePC 5.x onto SSDs that would otherwise be too small to use, such as the 2 GB SSDs in some very old HP thin clients. To do this, image a USB stick with RePC Live and boot this, then use TMS to install an SSH public key (see https://help.thinlinx.com/knowledgebase.php?article=7), SSH to the device as root, and run a command to copy RePC Live directly to the internal SSD, e.g. dd if=/dev/sdb of=/dev/sda bs=1048576 conv=fsync If all goes well, you should then be able to unplug the USB stick and boot TLXOS directly from the internal SSD. ## EFI-BOOTABLE REPC ISO The RePC 5.x ISO images now use rEFInd to provide an EFI boot capability, in addition to the existing ISOLinux Legacy boot capability. This allows you to use a real or virtual DVD to install RePC 5.x on new (in particular, Intel-branded) hardware that has a UEFI-only ("Legacy free") BIOS, or on a virtual machine which has been configured for EFI rather than Legacy (a.k.a. "BIOS") boot. We still recommend that wherever possible you use the USB installer instead, however.