composer versions and Constraints, update #composer

composer.txt

https://getcomposer.org/doc/articles/versions.md#writing-version-constraints
1.0 - 2.0 is equivalent to >=1.0.0 <2.1

~1.2 is equivalent to >=1.2 <2.0.0, while ~1.2.3 is equivalent to >=1.2.3 <1.3.0

^1.2.3 is equivalent to >=1.2.3 <2.0.0 as none of the releases until 2.0 should break backwards compatibility. 
pre-1.0 versions it also acts with safety in mind and treats ^0.3 as >=0.3.0 <0.4.0

1.2.3	=1.2.3.0-stable
>1.2	>1.2.0.0-stable
>=1.2	>=1.2.0.0-dev
>=1.2-stable	>=1.2.0.0-stable
<1.3	<1.3.0.0-dev
<=1.3	<=1.3.0.0-stable
1 - 2	>=1.0.0.0-dev <3.0.0.0-dev
~1.3	>=1.3.0.0-dev <2.0.0.0-dev
1.4.*	>=1.4.0.0-dev <1.5.0.0-dev

update.txt

lists all updates.
composer update --dry-run 
composer update --dry-run --with-dependencies
then
composer update package/name

https://www.youtube.com/watch?v=jUsEqy1YRzA 32:00

composer lock cannot be updated witouth conflicts. to overcome:
git checkout <branch> --composer.lock   // branch - base branch to you are merging (e.g. master)
-repeat composer update <list of deps>
store parameters in commit message
seperate commit for lock file update