diff --git a/roles/init-server/tasks/contingent/pkg/julia.yml b/roles/init-server/tasks/contingent/pkg/julia.yml
index bebb4aa..c9faecd 100644
--- a/roles/init-server/tasks/contingent/pkg/julia.yml
+++ b/roles/init-server/tasks/contingent/pkg/julia.yml
@@ -27,6 +27,6 @@
     - julia
     - julialauncher
     - juliaup
-- name: Reboot machine for shell environment change
-  ansible.builtin.reboot:
-    msg: Rebooting machine
\ No newline at end of file
+# - name: Reboot machine for shell environment change
+#   ansible.builtin.reboot:
+#     msg: Rebooting machine
\ No newline at end of file
diff --git a/roles/init-server/tasks/contingent/pkg/nvm.yml b/roles/init-server/tasks/contingent/pkg/nvm.yml
index ad8d869..21b03a6 100644
--- a/roles/init-server/tasks/contingent/pkg/nvm.yml
+++ b/roles/init-server/tasks/contingent/pkg/nvm.yml
@@ -89,7 +89,7 @@
         group: root
         state: link
       loop: "{{ prebuilt_nodepaths | product(['node']) }}"
-- name: Reboot machine for shell environment change
-  ansible.builtin.reboot:
-    msg: Rebooting machine
+# - name: Reboot machine for shell environment change
+#   ansible.builtin.reboot:
+#     msg: Rebooting machine
 
diff --git a/roles/init-server/tasks/contingent/pkg/radicle.yml b/roles/init-server/tasks/contingent/pkg/radicle.yml
index cb6bf9b..7351e06 100644
--- a/roles/init-server/tasks/contingent/pkg/radicle.yml
+++ b/roles/init-server/tasks/contingent/pkg/radicle.yml
@@ -46,6 +46,6 @@
         - git-remote-rad
         - rad-id
         - rad-patch
-- name: Reboot machine for shell environment change
-  ansible.builtin.reboot:
-    msg: Rebooting machine
\ No newline at end of file
+# - name: Reboot machine for shell environment change
+#   ansible.builtin.reboot:
+#     msg: Rebooting machine
\ No newline at end of file
diff --git a/roles/init-server/tasks/contingent/pkg/rustup.yml b/roles/init-server/tasks/contingent/pkg/rustup.yml
index c78c1cc..606684a 100644
--- a/roles/init-server/tasks/contingent/pkg/rustup.yml
+++ b/roles/init-server/tasks/contingent/pkg/rustup.yml
@@ -23,6 +23,6 @@
     state: link
   loop:
     - rustup
-- name: Reboot machine for shell environment change
-  ansible.builtin.reboot:
-    msg: Rebooting machine
\ No newline at end of file
+# - name: Reboot machine for shell environment change
+#   ansible.builtin.reboot:
+#     msg: Rebooting machine
\ No newline at end of file
diff --git a/roles/init-server/tasks/contingent/pkg/uv.yml b/roles/init-server/tasks/contingent/pkg/uv.yml
index 8c72c82..c11b8ad 100644
--- a/roles/init-server/tasks/contingent/pkg/uv.yml
+++ b/roles/init-server/tasks/contingent/pkg/uv.yml
@@ -24,6 +24,6 @@
   loop:
     - uv
     - uvx
-- name: Reboot machine for shell environment change
-  ansible.builtin.reboot:
-    msg: Rebooting machine
\ No newline at end of file
+# - name: Reboot machine for shell environment change
+#   ansible.builtin.reboot:
+#     msg: Rebooting machine
\ No newline at end of file
diff --git a/roles/init-server/tasks/core@install-pkgs.yml b/roles/init-server/tasks/core@install-pkgs.yml
index b12f880..21a8582 100644
--- a/roles/init-server/tasks/core@install-pkgs.yml
+++ b/roles/init-server/tasks/core@install-pkgs.yml
@@ -45,9 +45,55 @@
       when: ansible_facts["os_family"] == "Debian"
       become: true
       block:
+        - name: Creating core OS repository sources for package manager
+          when: ansible_facts["os_family"] == "Debian"
+          ansible.builtin.deb822_repository:
+            name: "{{ item.name }}"
+            uris: "{{ item.sources }}"
+            types: "{{ item.types }}"
+            suites: "{{ item.suites }}"
+            components: "{{ item.comps }}"
+            signed_by: "{{ item.sigkey }}"
+            state: present
+          loop:
+            - name: debian-trixie
+              sources: "http://deb.debian.org/debian/"
+              sigkey: /usr/share/keyrings/debian-archive-keyring.gpg
+              types:
+                - deb-src
+                - deb
+              suites:
+                - trixie
+                - trixie-updates
+              comps:
+                - main
+                - non-free-firmware
+                - contrib
+            - name: debian-trixie-security
+              sources: "http://security.debian.org/debian-security"
+              sigkey: /usr/share/keyrings/debian-archive-keyring.gpg
+              types:
+                - deb-src
+                - deb
+              suites: trixie-security
+              comps:
+                - main
+                - non-free-firmware
+                - contrib
+        - name: Remove previous core OS repository sources for package manager
+          ansible.builtin.file:
+            path: /etc/apt/sources.list
+            state: absent
+        # @TODO uncomment below before continuing with testing previous task
+        # - name: Premature end of play
+        #   ansible.builtin.meta: end_play
         - name: Updating package cache
           ansible.builtin.apt:
             update_cache: true
+        - name: Updating package cache
+          ansible.builtin.apt:
+            upgrade: dist
+            autoremove: true
         - name: Registering a package source
           when: item.sources != None
           ansible.builtin.deb822_repository:
@@ -59,24 +105,22 @@
             signed_by: "{{ item.sigkey }}"
             state: present
           loop: "{{ ((pkgs.mngr.core | default([]))) }}"
+        - name: Updating package cache
+          ansible.builtin.apt:
+            update_cache: true
         - name: Installing a local package in managed node
           when: item.uri != None
           ansible.builtin.apt:
             deb: "{{ item.uri }}"
             state: present
-          # @TODO add a default value for notify
-          # notify: "{{ item.name }}"
+          notify: "{{ item.handler | default('default') }}"
           loop: "{{ (pkgs.mngr.core | default([])) | selectattr('uri', 'search', '\\.deb$') }}"
-        - name: Updating package cache
-          ansible.builtin.apt:
-            update_cache: true
         - name: Installing a package
           when: item.name != None and item.uri == None
           ansible.builtin.package:
             name: "{{ item.name }}"
-            state: latest
-            # @TODO add a default value for notify
-          # notify: "{{ item.name }}"
+            state: present
+          notify: "{{ item.handler | default('default') }}"
           loop: "{{ ((pkgs.mngr.core | default([]))) | rejectattr('uri', 'search', '\\.deb$') }}"
       tags:
         - get_mngr_pkgs
@@ -94,12 +138,15 @@
             group: "{{ ansible_user }}"
             force: true
             mode: "744"
-          # @TODO add a default value for notify
-          notify: "{{ ((pkgs.script.core | default([])))[idx].name }}"
+          notify: "{{ ((pkgs.script.core | default([])))[idx].handler | default('default') }}"
           loop: "{{ (pkgs.script.core | default([])) }}"
           loop_control:
             index_var: idx
           register: install_scripts
+        - name: Reboot machine for shell environment change
+          become: true
+          ansible.builtin.reboot:
+            msg: Rebooting machine
       tags:
         - get_script_pkgs
     - name: Installing software by building it from source archives
@@ -131,16 +178,21 @@
           loop_control:
             index_var: idx
         - name: Unarchiving software build archive
+          become: true
+          become_user: "{{ current_user.stdout }}"
           when: item.dest != None and (((pkgs.script.core | default([]))) | length) > 0
           ansible.builtin.unarchive:
             src: "{{ item.dest }}"
             remote_src: true
             dest: "{{ ansible_user_home.stdout }}/downloads/archives/released/{{ ((pkgs.archive.core | default([])))[idx].name }}/"
-          # @TODO add a default value for notify
-          notify: "{{ ((pkgs.archive.core | default([])))[idx].name }}"
+          notify: "{{ ((pkgs.archive.core | default([])))[idx].handler | default('default') }}"
           loop: "{{ archived_builds.results }}"
           loop_control:
             index_var: idx
+        - name: Reboot machine for shell environment change
+          become: true
+          ansible.builtin.reboot:
+            msg: Rebooting machine
       tags:
         - get_archive_pkgs
     - name: Installing software from source git repositories
@@ -155,9 +207,12 @@
             version: "{{ item.branch }}"
             clone: true
             single_branch: true
-          # @TODO add a default value for notify
-          notify: "{{ item.name }}"
+          notify: "{{ item.handler | default('default') }}"
           loop: "{{ (pkgs.git_repos.core | default([])) }}"
           register: installation_repos
+        - name: Reboot machine for shell environment change
+          become: true
+          ansible.builtin.reboot:
+            msg: Rebooting machine
       tags:
         - get_git_pkgs
diff --git a/roles/init-server/tasks/userspace@install-pkgs.yml b/roles/init-server/tasks/userspace@install-pkgs.yml
index b4b9398..a823354 100644
--- a/roles/init-server/tasks/userspace@install-pkgs.yml
+++ b/roles/init-server/tasks/userspace@install-pkgs.yml
@@ -46,9 +46,55 @@
       when: ansible_facts["os_family"] == "Debian"
       become: true
       block:
+        - name: Creating core OS repository sources for package manager
+          when: ansible_facts["os_family"] == "Debian"
+          ansible.builtin.deb822_repository:
+            name: "{{ item.name }}"
+            uris: "{{ item.sources }}"
+            types: "{{ item.types }}"
+            suites: "{{ item.suites }}"
+            components: "{{ item.comps }}"
+            signed_by: "{{ item.sigkey }}"
+            state: present
+          loop:
+            - name: debian-trixie
+              sources: "http://deb.debian.org/debian/"
+              sigkey: /usr/share/keyrings/debian-archive-keyring.gpg
+              types:
+                - deb-src
+                - deb
+              suites:
+                - trixie
+                - trixie-updates
+              comps:
+                - main
+                - non-free-firmware
+                - contrib
+            - name: debian-trixie-security
+              sources: "http://security.debian.org/debian-security"
+              sigkey: /usr/share/keyrings/debian-archive-keyring.gpg
+              types:
+                - deb-src
+                - deb
+              suites: trixie-security
+              comps:
+                - main
+                - non-free-firmware
+                - contrib
+        - name: Remove previous core OS repository sources for package manager
+          ansible.builtin.file:
+            path: /etc/apt/sources.list
+            state: absent
+        # @TODO uncomment below before continuing with testing previous task
+        # - name: Premature end of play
+        #   ansible.builtin.meta: end_play
         - name: Updating package cache
           ansible.builtin.apt:
             update_cache: true
+        - name: Updating package cache
+          ansible.builtin.apt:
+            upgrade: dist
+            autoremove: true
         - name: Registering a package source
           when: item.sources != None
           ansible.builtin.deb822_repository:
@@ -60,32 +106,30 @@
             signed_by: "{{ item.sigkey }}"
             state: present
           loop: "{{ (pkgs.mngr.userspace | default([])) }}"
+        - name: Updating package cache
+          ansible.builtin.apt:
+            update_cache: true
         - name: Installing a local package in managed node
           when: item.uri != None
           ansible.builtin.apt:
             deb: "{{ item.uri }}"
             state: present
-          # @TODO add a default value for notify
-          # notify: "{{ item.name }}"
+          notify: "{{ item.handler | default('default') }}"
           loop: "{{ (pkgs.mngr.userspace | default([])) | selectattr('uri', 'search', '\\.deb$') }}"
-        - name: Updating package cache
-          ansible.builtin.apt:
-            update_cache: true
         - name: Installing a package
           when: item.name != None and item.uri == None
           ansible.builtin.package:
             name: "{{ item.name }}"
             state: latest
-          # @TODO add a default value for notify
-          # notify: "{{ item.name }}" # @TODO create corresponding roles/init-vps handlers
+          notify: "{{ item.handler | default('default') }}" # @TODO create corresponding roles/init-vps handlers
           loop: "{{ (pkgs.mngr.userspace | default([])) | rejectattr('uri', 'search', '\\.deb$') }}"
       tags:
         - get_mngr_pkgs
     - name: Installing software by executing installation shell scripts
       become: true
-      become_user: "{{ current_user.stdout }}"
       block:
         - name: Acquiring installation shell script
+          become_user: "{{ current_user.stdout }}"
           when: item.src != None and ((pkgs.script.userspace | default([])) | length) > 0
           ansible.builtin.uri:
             url: "{{ item.src }}"
@@ -95,12 +139,14 @@
             group: "{{ ansible_user }}"
             force: true
             mode: "744"
-          # @TODO add a default value for notify
-          notify: "{{ (pkgs.script.userspace | default([]))[idx].name }}"
+          notify: "{{ (pkgs.script.userspace | default([]))[idx].handler | default('default') }}"
           loop: "{{ (pkgs.script.userspace | default([])) }}"
           loop_control:
             index_var: idx
           register: install_scripts
+        - name: Reboot machine for shell environment change
+          ansible.builtin.reboot:
+            msg: Rebooting machine
       tags:
         - get_script_pkgs
     - name: Installing software by building it from source archives
@@ -139,37 +185,35 @@
             dest: "{{ ansible_user_home.stdout }}/downloads/archives/released/{{ (pkgs.archive.userspace | default([]))[idx].name }}/"
             owner: "{{ ansible_user }}"
             group: "{{ ansible_user }}"
-          # @TODO add a default value for notify
-          notify: "{{ (pkgs.archive.userspace | default([]))[idx].name }}"
+          notify: "{{ (pkgs.archive.userspace | default([]))[idx].handler | default('default') }}"
           loop: "{{ archived_builds.results }}"
           loop_control:
             index_var: idx
+        - name: Reboot machine for shell environment change
+          become: true
+          ansible.builtin.reboot:
+            msg: Rebooting machine
       tags:
         - get_archive_pkgs
     - name: Installing software from source git repositories
       block:
         - name: Clone git bare repository
-          when: item.src != None
           become: true
           become_user: "{{ current_user.stdout }}"
+          when: item.src != None
           ansible.builtin.git:
             repo: "{{ item.src }}"
             dest: "{{ ansible_user_home.stdout }}/repos/.foreign/{{ item.name }}"
             version: "{{ item.branch }}"
             clone: true
             single_branch: true
+          notify: "{{ item.handler | default('default') }}"
           loop: "{{ (pkgs.git_repos.userspace | default([])) }}"
           register: installation_repos
-        # - name: Changing ownership of specific repo subdirectory
-        #   become: true
-        #   become_user: "{{ current_user.stdout }}"
-        #   ansible.builtin.file:
-        #     path: "{{ ansible_user_home.stdout }}/repos/.foreign/{{ item.name }}"
-        #     recurse: true
-        #     owner: "{{ ansible_user }}"
-        #     group: "{{ ansible_user }}"
-        #   notify: "{{ item.name }}"
-        #   loop: "{{ (pkgs.git_repos.userspace | default([])) }}"
+        - name: Reboot machine for shell environment change
+          become: true
+          ansible.builtin.reboot:
+            msg: Rebooting machine
       tags:
         - get_git_pkgs
 # @TODO add a reboot either here or in any of the handlers potentially notified from here in