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KDE Display Manager

The KDE Display Manager (KDM) was the original graphical login program developed by the project for the , serving as the default display manager for early versions of the desktop environment. Introduced alongside 1.0 in 1998, KDM provided users with a customizable interface for authentication, session selection, and system shutdown options, while remaining independent of specific desktop environments to support launching various window managers. However, due to its bespoke design becoming outdated, KDM was retired with the release of 5 in 2014 and replaced by the (SDDM). SDDM, a lightweight QML-based display manager initially created for Qt desktops, became the recommended choice for and later versions, offering support for both X11 and sessions along with highly themeable interfaces using QtQuick for smooth animations. Developed independently but adopted and maintained in collaboration with —becoming officially part of the KDE project in 2023—SDDM emphasized simplicity, speed, and minimal dependencies on , XCB, and , while enabling features like passwordless login and customizable greeters. Despite its advantages, SDDM's single-process greeter architecture limited deeper integration with Plasma's features, such as and multi-monitor support, prompting ongoing maintenance challenges. In March 2025, KDE developers announced the development of Plasma Login Manager, a forked and redesigned successor to SDDM aimed at resolving these integration issues through a multi-process architecture, enhanced compatibility, and native support for components like wallpapers and virtual keyboards. As of November 2025, the project remains in prototype stage, with repositories hosted on Invent and focused on achieving feature parity before potential distribution adoption in future releases. This evolution reflects 's commitment to modernizing login experiences while prioritizing accessibility, security, and seamless desktop integration.

Background

Display Managers in Computing

A display manager, also known as a , is a program in operating systems that appears at the end of the boot process, replacing the default text-based shell to facilitate user login into a graphical session. It initializes and starts a display server, such as X11 or , allowing users to authenticate and select a before launching the full graphical session. This component serves as the entry point for graphical , managing the transition from system boot to an interactive user environment on local or remote displays. Historically, display managers evolved from text-based login mechanisms like getty, a foundational Unix utility dating back to early versions of the operating system, which handled serial terminal connections and prompted for credentials on physical or virtual terminals. The first graphical display manager, , emerged in the 1980s with the release of X11R3 in 1988, developed by Keith Packard at the MIT X Consortium to address the needs of X terminals and support remote logins via the X Display Manager Control Protocol (XDMCP). This marked a shift toward graphical interfaces in multi-user Unix systems, building on the X Window System's architecture to provide a more user-friendly alternative to command-line logins. Common functions of display managers include user authentication, where credentials are verified to grant access; session selection, enabling users to choose from available desktop environments such as or others; and management of virtual terminals, including switching between console and graphical modes. For authentication, they integrate with Pluggable Authentication Modules (), a framework that standardizes credential verification across applications in systems. Examples of widely used display managers include GDM, the Display Manager, which runs in the background to manage X or servers for local and remote logins, and , a lightweight, extensible option supporting multiple front-ends for customizable login interfaces. Display managers interact with init systems, such as , which orchestrates boot processes and starts graphical sessions via targets like graphical.target, enabling services like display managers to launch automatically. This integration ensures seamless session management, including activation of user-specific resources upon , while relying on for secure authentication against local or networked backends. Desktop environments like Plasma depend on display managers to initiate sessions, providing the foundational graphical that precedes the full experience.

Role in KDE Plasma

KDE Plasma serves as a widget-based that relies on a display manager to facilitate seamless user and session , enabling users to access the customizable workspace efficiently upon system boot. This integration ensures that the graphical interface aligns with 's core architecture, where widgets provide dynamic, interactive elements on the and panels for tasks like system monitoring and application launching. In the KDE ecosystem, the display manager plays a crucial role in maintaining consistency in theming across the login screen and the subsequent session, leveraging shared resources to apply color schemes, icons, and visual styles without disruption. It also supports the ongoing transition to by handling session initialization compatible with modern display protocols, while accommodating multi-user environments through features like per-user keyboard layouts and virtual input devices for diverse hardware setups. This alignment with 's emphasis on user-centric design prevents fragmentation in the , particularly in scenarios involving multiple monitors or high-DPI displays. KDE's design philosophy prioritizes modularity and -based components, allowing the display manager to integrate deeply with Plasma's look-and-feel through reusable modules that handle rendering and configuration. This approach promotes adaptability, where components can be extended or replaced without overhauling the entire system, fostering a cohesive environment built on open-source principles. For instance, 's enables efficient theming propagation and effect rendering, such as enhanced desktop grids, directly within the login process. A key challenge in the KDE context involves balancing with X11-based sessions—still prevalent for certain legacy applications—against the forward migration to , which offers superior security and handling but requires refined session management to avoid issues like inconsistent display detection or input handling. Display managers address this by supporting dual-protocol initialization, ensuring smooth transitions while mitigating compatibility gaps in edge cases.

Historical Development

Origins of KDM

The Display Manager (KDM) was launched in 1998 alongside the initial release of the 1.0 , serving as its default display manager to handle user authentication and session initiation on systems. Developed by the project team, KDM was created to supplant the generic (XDM) with a solution offering tighter integration for 's ecosystem, including support for its session management and user interface standards. Early development of KDM involved key contributions from KDE founders such as and Steffen Hansen, who addressed initial stability issues in the codebase. The project originated from the need for a display manager that aligned with KDE's emphasis on a consistent, user-centric experience, drawing directly from the while extending its capabilities for graphical login processes. KDM was built upon the version 11 (X11) as its foundational display server protocol, ensuring compatibility with existing Unix workstations. At its core, KDM leveraged Trolltech's framework for constructing its graphical user interface elements, enabling a Qt-based interface that could be customized to reflect 's visual aesthetic and . This approach facilitated seamless session startup, allowing users to select and launch sessions directly from the prompt. The inaugural version, KDM 1.0, was released on July 12, 1998, concentrating on essential functionalities such as username/password authentication, session selection, and basic system shutdown options without advanced theming or remote display support at launch.

Key Milestones and Releases

KDM's development closely paralleled the evolution of the desktop environment, with significant enhancements tied to major releases. The release of 2.0 on October 23, 2000, introduced comprehensive theming support across the desktop, including for the login manager, allowing users to customize the appearance of KDM via widget styles and imported themes from other environments like and . During the 3.x series, released between 2002 and 2008, KDM received improvements in multi-user support, facilitating better handling of concurrent sessions and user authentication in shared environments. The KDE 4.x series (2008–2014) saw KDM more tightly integrated with the new Plasma desktop shell, benefiting from enhanced stability and visual consistency with Plasma's widget-based architecture. KDM version 4.11, part of the 4.11 released on August 14, 2013, marked the last major update, with a focus on bug fixes to improve X11 stability and overall reliability. In 2013, KDE began signaling a shift away from KDM in preparation for 5, citing ongoing maintenance challenges amid the transition to 5 and modern display protocols. KDM reached end-of-life when it was removed from KDE development with the release of 5 in 2014, though KDE 4 support continued until 2016; it remains available in some legacy distributions as of 2025. During KDE's prominence in the , KDM served as the default in millions of installations worldwide, contributing to the environment's widespread adoption on distributions.

KDM Features and Functionality

Core Capabilities

KDM provides essential authentication mechanisms through its integration with the Pluggable Authentication Modules (PAM) framework, enabling secure verification of usernames and passwords during the graphical login process. This allows for flexible configuration of authentication methods. In terms of session management, KDM initiates user sessions by .desktop files located in directories such as /usr/share/xsessions, which define available environments and managers for selection at . Additionally, it supports the Control Protocol (XDMCP) to facilitate remote logins over the network, allowing connections from thin clients or other systems to the graphical . Theming in KDM is achieved through XML-based files, which enable customization of visual elements including backgrounds, fonts, and overall layouts while incorporating KDE's color schemes for consistency. These themes are defined in dedicated directories and can be selected via the kdmrc , providing a modular approach to appearance without altering core functionality. KDM handles virtual consoles by supporting standard key combinations like Ctrl+Alt+F1 through F6 to switch between the graphical screen and text-based terminals, ensuring access to modes or even during graphical operation. For diagnostics, KDM generates detailed logs in /var/log/kdm.log, capturing events such as attempts, errors, and session startups to aid in issues like failed authentications or problems.

Integration with KDE

KDM was specifically tailored for the desktop environment, with deep integration into its components to provide a cohesive . In 4, upon user login, the started session applied the user's configured theme, wallpaper, and panel layouts for a consistent appearance. KDM provided a themable interface using 's standard visual styles, minimizing discrepancies between the login screen and the subsequent desktop session. KDM relied fully on the Qt framework for all rendering and user interface elements, as it was developed as a native KDE application within the Qt-based ecosystem. This dependency eliminated potential conflicts with external graphics libraries, allowing KDM to leverage 's widget system for efficient, native-looking graphical components like the login dialog and theme previews. Configuration of KDM was integrated into the KDE Control Center (kcontrol), where users could access the Login Manager module to edit settings such as , greetings, and session behaviors. This module synchronized changes with broader KDE system settings, including user avatars displayed on the login screen, which were sourced from ~/.face.icon files or system-wide directories for a unified profile management across the desktop. KDM supported multi-desktop environments by allowing session selection from its interface, enabling switches to alternatives like while defaulting to and optimizing for KDE sessions through prioritized entries in the kdmrc configuration file's SessionTypes section. This flexibility maintained KDM's role as a KDE-centric without compromising . For compatibility with older KDE versions, KDM incorporated power management hooks that interfaced with legacy shutdown and reboot mechanisms, configurable via kdmrc options such as ShutdownButton to control access levels (e.g., RootOnly) and ensure reliable system operations from the login prompt.

Transition and Replacement

Reasons for Deprecation

The deprecation of KDM in stemmed primarily from its aging codebase, which was built on Qt 4 and not ported to Qt 5, making maintenance unsustainable as Plasma transitioned to the new framework in 2014. This migration challenge highlighted KDM's limitations, as porting efforts were abandoned in favor of a cleaner, more modern alternative aligned with Plasma's adoption of for user interfaces. KDM's exclusive reliance on X11 further exacerbated its incompatibility with emerging display protocols, as began preparing support starting in 2014 to enable hardware-accelerated and improved security. Unlike SDDM, which incorporated compatibility through compositors like , KDM lacked any pathway to this next-generation protocol, rendering it obsolete for future-oriented development. Performance concerns also contributed, with KDM exhibiting slower startup times and higher resource usage compared to lighter display managers, particularly on modern hardware where efficiency became a priority. Community reports in from 2010 to 2013 frequently highlighted persistent issues, such as incomplete multi-monitor support where login effects failed on secondary displays and theming inconsistencies across setups. By 5.2 in 2015, official documentation explicitly positioned SDDM as the recommended and future-standard display manager, marking the formal shift away from KDM to streamline integration and reduce maintenance overhead.

Adoption of SDDM

SDDM began as an independent open-source project in March 2013, initiated by community developers including contributors like David Edmundson, to create a modern, lightweight display manager using for Qt-based desktop environments. In early 2014, as prepared the release of 5, the project gained official endorsement from the community, positioning SDDM as the direct successor to the aging KDM due to its better alignment with contemporary technologies like support and a fresh codebase free from legacy XDM dependencies. The integration of SDDM into the ecosystem accelerated with the launch of Plasma 5.0 on July 15, 2014, which excluded KDM entirely and prompted distributions to adopt SDDM as the default for new Plasma installations. Major Linux distributions quickly followed suit: switched to SDDM as the default for its KDE spin ahead of Fedora 20 in late 2013 and maintained it through Plasma 5 transitions, while designated SDDM as the preferred display manager for Plasma shortly after the 5.0 release. This shift ensured seamless session management for Plasma users, with SDDM's QML-based interface providing a more responsive and customizable login experience compared to KDM's constraints. To support users migrating from KDM, KDE introduced the sddm-kcm module in Plasma 5.2, released in January 2015, which embeds SDDM configuration directly into the Plasma System Settings application. This tool enables straightforward adjustments to themes, wallpapers, and user interfaces, effectively bridging configurations from prior KDM setups without requiring manual file edits. Community-driven ports of popular KDM themes to SDDM further eased the visual transition, preserving familiar aesthetics for long-time KDE users during the rollout. By 2016, SDDM had achieved widespread use in KDE Plasma deployments across key distributions including and , solidifying its role as the and rendering KDM obsolete in active development branches. This adoption process not only modernized login management but also fostered greater interoperability within the Qt ecosystem, with SDDM's ongoing maintenance ensuring long-term stability for users.

SDDM as Default Display Manager

Development History

SDDM was initially developed in as a lightweight, QML-based display manager intended as a modern alternative to the aging KDM, with its first stable release occurring on of that year. The project was started by Abdurrahman Avci to provide a fast and themeable solution for Qt-based desktop environments, leveraging for fluid user interfaces. Early development emphasized simplicity and cross-desktop compatibility, quickly gaining traction among lightweight Qt projects like and Liri. KDE's involvement deepened in 2014, coinciding with the 5 release cycle, when 0.10 of SDDM was aligned for seamless as the recommended display manager, replacing KDM. Subsequent releases have followed 's annual cadence, ensuring compatibility with evolving technologies such as updates and theming frameworks. This synchronization facilitated SDDM's adoption across distributions, with developers contributing significantly to maintenance and enhancements. Key milestones include version 0.18 in July 2018, which introduced support for 5.11, theme-supplied user avatars, automatic HighDPI detection, and ConsoleKit compatibility, broadening its appeal for diverse hardware setups. Later, version 0.20, released in June 2023, enhanced the theming engine with better 5.15 integration, improved error handling for authentication, and initial experimental support for running the greeter under while separating Wayland and X11 processes. These updates refined customization options, allowing more dynamic and performant themes without compromising stability. SDDM's codebase is hosted on GitHub under the sddm organization, with primary development driven by KDE contributors alongside input from LXQt and other communities; by 2025, the project had amassed over 100 unique contributors through pull requests and issue resolutions. This collaborative model has sustained steady progress, including porting efforts to newer Qt versions. In 2024, version 0.21 focused on bridging Qt 5 and Qt 6 compatibility for the greeter, enabling co-installation and smoother transitions for distributions upgrading to Plasma 6, alongside refinements to Wayland keyboard layouts and PAM service handling on FreeBSD. These changes addressed lingering authentication edge cases and bolstered overall reliability, though no major CVEs were reported specifically targeting SDDM's authentication module that year.

Technical Architecture

SDDM's technical architecture revolves around a set of core components designed for modularity and efficiency in managing user logins and sessions. The greeter, responsible for the graphical login interface, is built using QtQuick with , enabling declarative UI development that supports animations, layouts, and interactive elements without compromising performance. This choice leverages Qt's rendering for smooth visuals on modern hardware. The backend, implemented in C++, handles critical operations such as authentication via , session launching, and interaction with the display server, ensuring secure and reliable session initialization independent of the frontend. Themes are defined through a combination of configuration files for metadata and settings, alongside files for visual and behavioral customization, allowing themes to override default behaviors like user list display or input handling while maintaining compatibility across distributions. A key aspect of SDDM's design is its support for multiple display servers, with full compatibility for X11 as the primary backend, including features like virtual terminal switching and Xauthority management. For , SDDM offers partial support through integration with systemd-logind since 2018, enabling the launch of unprivileged sessions while the greeter itself runs on X11; experimental full greeter support was introduced in version 0.20.0 in 2023, utilizing QtWayland for . This hybrid approach ensures broad compatibility during the transition to , with logind providing seat and session tracking to coordinate multi-user environments. The architecture emphasizes through separation, where the sddm daemon runs as a system service to manage overall display manager lifecycle, and the sddm-greeter operates as an auxiliary dedicated to rendering the login UI. This isolation prevents greeter crashes from affecting the daemon or active sessions, enhancing system resilience; for instance, if the greeter fails due to a theme error, the daemon can restart it without disrupting ongoing operations. Communication between components occurs via and Unix sockets, minimizing overhead while supporting features like queries. SDDM relies on key dependencies to integrate with modern desktop environments, including Qt6 as the foundational framework since KDE Plasma 6's release in , which provides updated modules and improved rendering capabilities over prior Qt5 versions. Systemd-logind is utilized by default for user session tracking, seat assignment, and idle detection, falling back to consolekit if unavailable, though this ensures seamless operation in systemd-based systems. The build process employs for cross-platform compilation, with configurable options to enable GPU acceleration via in the QtQuick renderer, allowing hardware-accelerated effects in themes such as blurring or particle animations when supported by the graphics driver. This setup facilitates easy integration into distributions, with build flags for features like helper binaries for during session startup.

SDDM Features and Customization

User Interface Elements

The greeter in SDDM presents a modern, QtQuick-based interface designed for smooth animations and , with the default Breeze theme providing a clean, integrated look that aligns with 's aesthetic. This theme incorporates wallpaper integration, allowing users to apply desktop backgrounds directly to the screen via under Workspace > Startup and Shutdown > Screen (SDDM), ensuring visual consistency between the greeter and the . Additionally, the greeter supports functionality, configurable through the InputMethod option set to qtvirtualkeyboard, which displays an on-screen keyboard for or touch-based input during . The login form features prominent username and fields, a dropdown menu for session selection from available X11 or desktops (sourced from /usr/share/xsessions or /usr/share/wayland-sessions), and power buttons for shutdown and reboot actions, all rendered as customizable QtQuick components that trigger system commands like systemctl poweroff or reboot. These elements are positioned centrally on the screen, with user avatars optionally displayed from the /usr/share/sddm/faces directory to enhance identification. SDDM's theming system enables extensive customization, with themes installed in the /usr/share/sddm/themes/ directory and selected via the Current option in the [Theme] section of sddm.conf or through Plasma's graphical interface. Themes leverage QtQuick to support fluid animations, such as fade-ins for form elements or transitions during authentication, while accessibility features include high-contrast modes achievable through custom theme variants that adjust color schemes and text visibility. Theme creators can utilize provided models like userModel for dynamic content and keyboard objects for layout indicators, ensuring broad compatibility. In multi-monitor setups, SDDM extends the greeter across all displays using the screenModel to access geometries, but input focus defaults to the primary monitor as defined in the system's display configuration, preventing unintended interactions on secondary screens. This handling maintains a unified login experience while prioritizing the main display for the form and keyboard input. For input methods, SDDM supports IBus to facilitate non-Latin languages, configured by setting InputMethod=ibus in sddm.conf, which enables complex text composition for scripts like Cyrillic, Arabic, or Asian languages during username and password entry. Complementing this, the on-screen keyboard—activated for touch devices—adapts to IBus layouts, providing visual keys for non-Latin characters and improving usability on tablets or hybrid devices.

Security and Performance Aspects

SDDM incorporates several security measures to protect user authentication and session management. It relies on the Pluggable Authentication Modules () framework for credential verification, which supports secure transmission of authentication data through configured modules like pam_unix, ensuring passwords are not exposed in plaintext during login. Additionally, SDDM leverages systemd-logind for controlling greeter access to hardware resources such as DRM devices, reducing the by isolating privileged operations. For monitoring, PAM integration allows audit logging of failed login attempts via modules like pam_tally2, enabling administrators to track and respond to potential brute-force attacks. In terms of vulnerability history, SDDM has addressed notable issues through timely patches. A significant local vulnerability, CVE-2020-28049, affected versions prior to 0.19.0, where the startup process temporarily allowed unprivileged users to access sensitive files; this was fixed by improving command-line argument handling and authentication checks. KDE maintains regular reviews, with components like the SDDM configuration module (sddm-kcm) undergoing audits, as evidenced by openSUSE's evaluation prior to 6 integration to mitigate potential risks. On the performance front, SDDM is designed for efficiency using QtQuick for its greeter interface, enabling smooth animations and modular loading to minimize resource demands. Its idle RAM usage typically remains low, around 50-100 MB depending on theme complexity, though external display configurations can lead to unreleased allocations of up to 400 MB in some cases. SDDM's support for Wayland sessions enhances security by leveraging the protocol's inherent isolation, where each application runs in its own namespace, preventing one session from capturing input events like keystrokes from another to mitigate keylogging risks between users. This contrasts with X11's global input model and aligns with SDDM's modular architecture for session handling.

Emerging Plasma Login Manager

Announcement and Rationale

On March 26, 2025, KDE developer David Edmundson announced the initiation of a new project to develop the Plasma Login Manager, a successor to SDDM, through a detailed blog post outlining its roadmap and motivations. This announcement highlighted SDDM's upstream stagnation, where its desktop-agnostic design and theme-based customization have led to maintenance challenges and limited feature development, preventing seamless integration with Plasma's ecosystem. Additionally, the rationale emphasized the need for deeper Plasma integration, such as native support for Plasma widgets and components for power management, network handling, and multi-monitor setups, alongside the maturation of Wayland as a stable session protocol. The Plasma Login Manager was established as a fork of SDDM, branched to incorporate Plasma-specific enhancements while maintaining core functionality, and renamed to plasma-login-manager under the Plasma repository on Invent. A companion repository, plasma-login, was created for the frontend and settings interface, enabling a multi-process greeter that aligns with 's session startup process to reduce external dependencies and improve modularity. The primary goals include achieving comprehensive compatibility for modern hardware support, such as and high-DPI displays, and streamlining customization through 's rather than complex themes. The initial reception within the community was positive, with developers and users expressing support for addressing SDDM's longstanding integration gaps, and early prototypes demonstrating functional parity with SDDM while inviting community feedback via KDE's development channels.

Development Progress as of 2025

The Plasma Login Manager project, forked from SDDM to enable deeper integration with KDE Plasma, remains in the prototype stage as of November 2025, with ongoing development focused on establishing a stable foundation and achieving feature parity. Development efforts emphasize refactoring the greeter interface for improved modularity and expanding automated testing suites to ensure reliability across diverse hardware configurations. These changes aim to address key pain points inherited from SDDM, including display issues. The initiative is led by KDE developer David Edmundson, with contributions from more than 20 KDE developers who have collaborated through code reviews and feature implementations. Community involvement has been facilitated via KDE Invent's GitLab merge requests, where testers have reported issues and provided feedback on usability in real-world scenarios. As of November 2025, the manager offers robust performance in X11 sessions, while support remains experimental and is undergoing active refinement to resolve session handover and compositing challenges.

Comparisons Across Versions

KDM Versus SDDM

KDM and SDDM differ fundamentally in their architectural design, with KDM representing a tightly integrated, monolithic structure built on Qt4 as part of the 4 ecosystem, where core display management and components were developed as a single, cohesive unit. In comparison, SDDM adopts a more modular approach, separating concerns like , session management, and the greeter , while relying on QtQuick and for declarative UI development that enables hardware-accelerated animations and easier extensibility across multiple desktop environments. Compatibility is another key distinction, as KDM was designed exclusively for X11-based sessions, lacking support for emerging protocols like due to its development timeline in the early . SDDM, introduced as a cross-desktop solution, provides hybrid compatibility for both X11 and Wayland sessions, allowing users to select the appropriate backend at login and facilitating smoother transitions to modern compositors. Customization options highlight further evolution, with KDM relying on static XML files for themes that define , colors, and basic behaviors through declarative markup, offering straightforward but limited modifications via KDE's . SDDM advances this with dynamic scripting, enabling highly interactive and scriptable themes that include premade components like text inputs and virtual keyboards, along with callbacks for events such as , for unrestricted visual and functional tailoring. These differences align with their respective use cases: KDM persists in legacy environments tied to KDE 4 installations for maintaining compatibility with older software stacks, while SDDM powers modern KDE Plasma 5 and beyond, integrating seamlessly with current features like multi-monitor support and Wayland compositing.

SDDM Versus Plasma Login Manager

The KDE Simple Desktop Display Manager (SDDM) maintains a relatively loose coupling with the Plasma desktop environment, requiring developers to reimplement features like power management, network controls, and brightness adjustments that are natively available in Plasma sessions. In contrast, the Plasma Login Manager embeds Plasma widgets directly into its interface, enabling seamless synchronization with Plasma's system settings and startup processes for a more unified experience. This deeper integration in the Plasma Login Manager reduces redundancy and allows for shared components, such as the same power management logic used in the desktop session. Regarding Wayland support, SDDM offers partial and experimental compatibility, relying on compositors like KWin but facing limitations in compositor-agnostic operations, such as keyboard layout configuration, which often lead to inconsistencies in multi-monitor setups. The Plasma Login Manager, built on KWin's Wayland-native architecture, targets full Wayland integration, aiming to eliminate these gaps by leveraging Plasma's established Wayland plumbing for smoother transitions and better hardware acceleration handling. This design positions it for comprehensive Wayland adoption, with development focusing on stability across diverse hardware configurations. Maintenance of SDDM is primarily community-driven, involving contributions from multiple desktop environments, which has resulted in duplicated efforts and challenges in merging Plasma-specific patches. The Login Manager, however, is owned and incubated by the core team, granting full control over its roadmap and enabling faster iteration on Plasma-aligned features without external dependencies. This shift promises more responsive maintenance tailored to Plasma's evolution. In terms of innovation, SDDM prioritizes stability through its theme-based customization, but its architecture mixes user interface logic with backend code, limiting extensibility and making additions like modular difficult. The Plasma Login Manager emphasizes extensibility by decoupling UI from logic, supporting architectures and with Plasma's biometric frameworks for features like . This approach fosters ongoing enhancements, such as advanced input methods and accessibility options, beyond SDDM's conservative updates. As of late 2025, SDDM continues to serve as the default display manager in major distributions like and for Plasma installations, ensuring broad compatibility and minimal disruption for users. The Plasma Login Manager remains in early development as of November 2025, with no official rollout or opt-in availability in current Plasma branches; distributions continue to use SDDM as the stable default. As of November 2025, development continues in prototype repositories without further public milestones or distribution adoption. This strategy mitigates risks, with full adoption expected as maturity improves.

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