Foreign taxes paid does not update or is capped ?

Foreign tax credit allowable is limited to amount US tax would have been on same type of income. Ref: https://www.irs.gov/forms-pubs/about-form-1116 

what category of foreign taxes.  

951A

Foreign Branch Income

Passive Category

General Category

901(g) Income

Certain income Resourced By Treaty

Lump Sum Distribution

Foreign Earned Income

the best way is to look at the form  page 1 shows the gross amount and page 2 shows the computation of the allowable amount.     Unused becomes a carryover, except for 951A FTC

Enter the unused foreign taxes in the
separate category from another tax year
that are eligible to be carried forward to
or back to 2018.
You can carry back 1 year and then
forward 10 years any foreign tax you
paid or accrued to any foreign country
or U.S. possession (reduced as
described under Line 12, later) on
income in a separate category that is
more than the limitation. First, apply the
excess to the earliest year to which it
may be carried. Then, apply it to the
next earliest year, and so on. The
carryback-carryforward period can't be
extended even if you are unable to take
a credit in one of the intervening years.
Special rules apply to the carryback
and carryforward of foreign taxes paid
or accrued on foreign oil and gas
income. In addition, a special transition
rule applies to the carryforward of
pre-2009 unused oil and gas extraction
taxes to years beginning after 2008.
See section 907(f).
No foreign tax carryovers are allowed
for foreign taxes paid or accrued on
section 951A income. Leave line 10 of
Form 1116 blank if you complete a Form

1116 for section 951A income as
carrybacks and carryovers are not
allowed for this category of income.
File Form 1040X or other amended
return and a revised Form 1116 for the
earlier tax year to which you are carrying
back excess foreign taxes.
Restrictions. You can't carry a credit
back to a tax year for which you claimed
a deduction, rather than a credit, for
foreign taxes paid or accrued. However,
you must reduce the amount of any
carryback or carryforward by the
amount that you would have used had
you chosen to claim a credit rather than
a deduction in that year.
If, for any year, you elected to claim
the foreign tax credit without filing Form
1116 (as explained earlier), the
following rules apply.
• You can't carry over unused foreign
taxes paid or accrued in a year to which
the election doesn't apply to or from any
year for which you made the election.
• The carryback-carryforward period
isn't extended if you are unable to use a
carryback or carryforward because you
made the election.
• Don't reduce the carryback or
carryforward by the amount you would
have used in the election year if you
hadn't made the election.
More information. See Pub. 514 for
more information on carryback and
carryforward provisions, including
examples.