# IMPORTANT - PLEASE READ: TLXOS 5.x has been released, including both a new Long Term Stable version (currently 5.0.1) and a progressive version (currently 5.2.1). TLXOS RPi 5.0.x LTS does **NOT** support the Raspberry Pi 5 - you must install RPi 5.2.x 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 (assuming you haven't 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.x LTS sizes exactly the same as those of TLXOS 4.x. TLXOS 5.2.x, 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.x is therefore now 4-5 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. Although the O/S itself is still 32-bit, TLXOS RPi 5.2.x now runs a 64-bit kernel, and consequently does not support Pi <= 2. A fully 64-bit variant of TLXOS RPi 5.2.x is also available, but this lacks VMware Horizon Client and therefore does not support Horizon mode (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.x LTS, which is still based on Debian 10 (Buster) might therefore prove to be a somewhat short-lived LTS sequence. Unlike 5.0.x LTS, the hypothetical 5.1.0 LTS would (mostly) support the Pi 5 and have a larger disk footprint similar to 5.2.x. Please note that unlike mainline Debian/Raspbian Bookworm, TLXOS 5.2.x continues to use X11, not Wayland, and a 4k page size. ## WHY IS 5.0.x LTS' KERNEL SO OLD? We couldn't use a 6.1 kernel in TLXOS 5.0.x for two reasons, both of which are related to our goal of minimizing the risk involved in a 4.x to 5.0.x 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.x 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.x'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 soon. In the meantime, you can try installing or upgrading to TLXOS SFF 5.0.x 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. The workarounds we used in TLXOS RPi 5.2.0 were clumsy, and we no longer recommend this release for use with the Pi 5 - please install or upgrade to 5.2.1 instead. For TLXOS RPi 5.2.1, we were better able to identify exactly what worked and what didn't on a Pi 5. It now features an up-to-date version of Workspace App, and an older version of Horizon Client (2212.1) that doesn't have a USB redirection problem. Horizon Client cannot be provided for the 64-bit TLXOS RPi 5.2.x variant because VMware have not ported Horizon Client to ARM64 yet. TLXOS RPi 5.2.x and TLXOS RPi64 5.2.x 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.x will overwrite TMS' copy of 32-bit RPi 5.2.x, and vice versa). 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. Please read https://help.thinlinx.com/knowledgebase.php?article=107 for more information on how to do this. ## 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.