Snap Nextcloud Upgrade from 16 to 19 occ Upgrade not Possible because php command not found

I tried to Follow the Tutorial That didnā€™t change ever since Versions even below 15.
I once installed nextcloud via snap by snap install nextcloud.
It installed Nextcloudb 16 at that time.
Here is the Docu that didnā€™t change for any major release.
ā€¦/15/ā€¦
https://docs.nextcloud.com/server/16/admin_manual/maintenance/package_upgrade.html
ā€¦/17/ā€¦
ā€¦/18/ā€¦
ā€¦/19/ā€¦

It Says I should run

sudo snap refresh nextcloud

so I did and it went through without any errors. It Upgraded to Nextcloud 19 for me.

But then, the Second Command just donā€™t work and I just couldnā€™t find anything to this online despite hours of research Iā€™m done with my nerves.
It Says:

sudo -u www-data php occ upgrade

but Iā€™m getting the Error PHP: command not found.
I donā€™t get it, how does nextcloud have even functioned before without PHP? and what is this occ stuff even? never heard off it as far as I can remember.

And I thought Updating and maintaining snap is easier but if the documentation always is wrongā€¦ I just canā€™t understand whatā€™s so difficult to write a correct Wiki/HowTo For once.

So Please could someone help me? I really really donā€™t want to lose all my data on this nextcloud instance and i simply donā€™t know what to do and canā€™t find anything olnine. I just donā€™t know what iā€™m doing wrong constantlyā€¦

Additinal Info:
uname -a

Linux cloud 4.9.0-11-amd64 #1 SMP Debian 4.9.189-3+deb9u1 (2019-09-20) x86_64 GNU/Linux

updatedb

command not found

php -v

command not found

locate /owncloud/occ

locate /nextcloud/occ

root@cloud /snap/nextcloud/current/bin # ls
ab mysql_upgrade
apxs mysqlxtest
certbot nextcloud-cron
chardetect nextcloud-fixer
checkgid occ
dbmmanage pasteurize
delay-on-failure pbr
disable-https pear
enable-https peardev
export-data pecl
fcgistarter php
futurize php-config
htcacheclean php-fpm
htdbm phpize
htdigest redis-benchmark
htpasswd redis-check-aof
httpd redis-check-rdb
httpd-wrapper redis-cli
httxt2dbm redis-sentinel
import-data redis-server
jws renew-certs
logresolve restart-apache
manual-install rotatelogs
mdns-publisher run-httpd
my_print_defaults run-mysql
mysql run-mysqldump
mysqlcheck run-php
mysqld setup-nextcloud
mysqld_safe start_mysql
mysqldump start-php-fpm
mysqldumpslow start-redis-server
root@cloud /snap/nextcloud/current/bin # sudo -u www-data php occ upgrade
sudo: php: command not found

is someone here at all?

i cant even open up an issue on githubā€¦ it just wont let meā€¦

Hi,

Upgrading between major versions isnā€™t allowed. You need to upgrade bewteen one version at the time, so in your case 15 --> 16 --> 17 --> 18 --> 19.

In the Nextcloud VM it would be possible to go that path, but Iā€™m not sure about the snap.