How to install kicad V5 when apt install only find V4 of it? (on linux mint LMDE)

I need to install KiCad V5 but when I use apt command it only could install Version 4 like this: notebook:/media/so/ACAC8B5FAC8B2346/Elasa/Softwares/Linux's/Electronic/Kicad/Libraries/kipi-0.2.1$ sudo apt-cache madison kicad kicad | 4.0.5+dfsg1-4~bpo8+1 | http://archive.debian.org/debian jessie-backports/main amd64 Packages kicad | 0.20140622+bzr4027-3 | http://ftp.de.debian.org/debian jessie/main amd64 Packages kicad | 0.20140622+bzr4027-3 | http://cdn-fastly.deb.debian.org/debian jessie/main amd64 Packages so@notebook:/media/so/ACAC8B5FAC8B2346/Elasa/Softwares/Linux's/Electronic/Kicad/Libraries/kipi-0.2.1$ apt-cache policy kicad kicad: Installed: (none) Candidate: 0.20140622+bzr4027-3 Version table: 4.0.5+dfsg1-4~bpo8+1 100 100 http://archive.debian.org/debian jessie-backports/main amd64 Packages 0.20140622+bzr4027-3 500 500 http://ftp.de.debian.org/debian jessie/main amd64 Packages 500 http://cdn-fastly.deb.debian.org/debian jessie/main amd64 Packages Also, I can not find the main zip file of kicad electrical software file via its download link for Linux mint , there is said to: > To install KiCad via the PPA, you can use the Software Manager: > > Open the Software Manager. > > Select 'Edit' → 'Software Sources…​'. > > Open the 'Other Software' tab. > > Click 'Add…​', and enter the PPA address: ppa:js-reynaud/kicad-5.1 and then click the 'Add Source' button. > > When prompted insert the administrator user password. > > Return to the Software Manager and view the Progress tab to see when the cache has finished updating. > > Return to the Software Manager main screen, search for 'kicad', and install it. > > The KiCad schematic library and docs are in separate packages. If you > want either of these install kicad-library and kicad-doc respectively. > > If you prefer to use the shell, you can enter these commands into a > terminal: sudo add-apt-repository --yes ppa:js-reynaud/kicad-5.1 sudo apt update sudo apt install --install-suggests kicad So there is no edit option in my Linux LMDE mint as you can see : Also i can not run this code :

aries/kipi-0.2.1$ sudo add-apt-repository --yes ppa:js-reynaud/kicad-5.1 
Adding PPAs is not supported

i asked about it here , anyway i tried to install v5 of it as recommended here , but as i mentioned i can not install it with it self site instruction. so i like to know where is the source file of the kicad V5 and or is it possible to install it via bash like: sudo apt install kicad=5 but there is only Kicad V4 as i said above: is this because Linux server setting, or is because i am from Iran( with many ISP filters from government side or international sanctions policy) . Update: based of this question some more information about my system setting:

$ inxi -Fxzd
System:
  Host: notebook Kernel: 4.9.0-9-amd64 x86_64 bits: 64 compiler: gcc v: 6.3.0 
  Desktop: Cinnamon 4.0.10 Distro: LMDE 3 Cindy base: Debian 9.3 stretch 
Machine:
  Type: Laptop System: LENOVO product: 80TV v: Lenovo ideapad 310-15IKB 
  serial:  
  Mobo: LENOVO model: Torronto 5C2 v: NO DPK serial:  
  UEFI [Legacy]: LENOVO v: 3JCN26WW date: 03/07/2017 
Battery:
  ID-1: BAT0 charge: 13.6 Wh condition: 13.6/30.0 Wh (45%) model: SMP L15M2PB3 
  status: Full 
CPU:
  Topology: Dual Core model: Intel Core i7-7500U bits: 64 type: MT MCP 
  arch: Kaby Lake rev: 9 L2 cache: 4096 KiB 
  flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 23232 
  Speed: 923 MHz min/max: 400/3500 MHz Core speeds (MHz): 1: 923 2: 801 3: 800 
  4: 800 
Graphics:
  Device-1: Intel vendor: Lenovo driver: i915 v: kernel bus ID: 00:02.0 
  Device-2: NVIDIA GM108M [GeForce 920MX] vendor: Lenovo driver: nouveau 
  v: kernel bus ID: 03:00.0 
  Display: x11 server: X.Org 1.19.2 driver: modesetting,nouveau 
  unloaded: fbdev,vesa resolution: 1920x1080~60Hz 
  OpenGL: renderer: Mesa DRI Intel HD Graphics 620 (Kabylake GT2) 
  v: 4.5 Mesa 13.0.6 direct render: Yes 
Audio:
  Device-1: Intel vendor: Lenovo driver: snd_hda_intel v: kernel bus ID: 00:1f.3 
  Sound Server: ALSA v: k4.9.0-9-amd64 
Network:
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet 
  vendor: Lenovo driver: r8168 v: 8.043.02-NAPI port: 5000 bus ID: 01:00.0 
  IF: enp1s0 state: up speed: 1000 Mbps duplex: full mac:  
  Device-2: Realtek RTL8821AE 802.11ac PCIe Wireless Network Adapter 
  vendor: Lenovo driver: rtl8821ae v: kernel port: 4000 bus ID: 02:00.0 
  IF: wlp2s0 state: up mac:  
  IF-ID-1: as0t0 state: unknown speed: 10 Mbps duplex: full mac: N/A 
  IF-ID-2: as0t1 state: unknown speed: 10 Mbps duplex: full mac: N/A 
  IF-ID-3: as0t2 state: unknown speed: 10 Mbps duplex: full mac: N/A 
  IF-ID-4: as0t3 state: unknown speed: 10 Mbps duplex: full mac: N/A 
  IF-ID-5: as0t4 state: unknown speed: 10 Mbps duplex: full mac: N/A 
  IF-ID-6: as0t5 state: unknown speed: 10 Mbps duplex: full mac: N/A 
  IF-ID-7: as0t6 state: unknown speed: 10 Mbps duplex: full mac: N/A 
  IF-ID-8: as0t7 state: unknown speed: 10 Mbps duplex: full mac: N/A 
Drives:
  Local Storage: total: 1.82 TiB used: 642.34 GiB (34.5%) 
  ID-1: /dev/sda vendor: Seagate model: ST2000LM003 HN-M201RAD size: 1.82 TiB 
  Optical-1: /dev/sr0 vendor: HL-DT-ST model: DVDRAM GUE0N rev: T.02 
  dev-links: cdrom,cdrw,dvd,dvdrw 
  Features: speed: 24 multisession: yes audio: yes dvd: yes 
  rw: cd-r,cd-rw,dvd-r,dvd-ram state: running 
Partition:
  ID-1: / size: 196.17 GiB used: 29.87 GiB (15.2%) fs: ext4 dev: /dev/sda7 
  ID-2: /home size: 196.17 GiB used: 182.16 GiB (92.9%) fs: ext4 dev: /dev/sda3 
Sensors:
  System Temperatures: cpu: 41.0 C mobo: N/A 
  Fan Speeds (RPM): N/A 
Info:
  Processes: 337 Uptime: 23h 18m Memory: 11.64 GiB used: 8.13 GiB (69.8%) 
  Init: systemd runlevel: 5 Compilers: gcc: 6.3.0 Shell: bash v: 4.4.12 
  inxi: 3.0.32

aries/kipi-0.2.1$ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 005: ID 0bda:0821 Realtek Semiconductor Corp. 
Bus 001 Device 004: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
Bus 001 Device 003: ID 174f:2408 Syntek 
Bus 001 Device 008: ID 046d:c077 Logitech, Inc. M105 Optical Mouse
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Thanks for your time and consideration